Impaginato 155 Adv. Hort. Sci., 2024 38(2): 155­167 DOI: 10.36253/ahsc­15691 Pigment composition and physico­ chemical parameters of Bittergourd (Momordica charantia L. cv. Jadeite) during postharvest period as influenced by illumination colors J.G. Ponteras 1 (*), J.D.C. Quisil 2 , F.M. Salas 3 1 Agriculture Department, Institute of Agricultural Technology and Entrepreneurial Studies, Southern Philippiness, Agribusiness and Marine and Aquatic School of Technology, Malita, Davao Occidental, Philippines. 2 College of Agriculture, Central Mindanao University, University Town, Musuan, Maramag, Bukidnon, Philippines. 3 Department of Pure and Applied Chemistry, College of Arts and Sciences, Visayas State University, Baybay City, Leyte, Philippines. Key words: Bittergourd, LED, pigmental composition, postharvest quality. Abstract: Fruits and vegetables that exhibit a higher chlorophyll content, as reflected in their visual appearance, are the preferred choice of consumers. The study aimed to evaluate the effects of Light Emitting Diodes (LEDs) on the physical, chemical, and pigmentation quality of bitter gourd using white, blue, and red at 1.5 W/135 lumens (Foshan Electrical and Lighting Co., Ltd [FSL], China). Bitter gourd, with a short postharvest life of 4­5 days due to physical and chemical disorders, was harvested weighing 300–400 g and 25 x 5 cm from the farm and subjected to varying illuminations within a 4­hour period for five days, with measurements taken daily. Statistical differences between treatments were observed in physicochemical parameters such as fruit shrivelling, yellowing, visual appearance, weight loss, dry matter content, total chlorophyll, pH values, and TA. The quality and shelf­life of bitter gourd fruits were found to be improved by the white LED. The visual appearance was maintained, and fruit shrivelling and yellowing were delayed, with lower weight loss observed. Slight changes in chlorophylls and carotenoids, vitamin C, and a shelf­life of 5 days were recorded. 1. Introduction Momordica charantia L. is known as bitter gourd, with its good nutritional and medicinal properties, is grown in approximately 340,000 ha (Dhillon et al., 2016) annually in tropical Asia, including Eastern Asia, India, and China, which is its center of origin (Behera et al., 2010; (*) Corresponding author: ponterasjohn@gmail.com Citation: PONTERAS J.G., QUISIL J.D.C. , SALAS F.M., 2024 ­ Pigment composition and physico‐chemi‐ cal parameters of Bittergourd (Momordica cha‐ rantia L. cv. Jadeite) during postharvest period as influenced by illumination colors. ­ Adv. Hort. Sci., 38(2): 155­167. Copyright: © 2024 Ponteras J.G., Quisil J.D.C. , Salas F.M. This is an open access, peer reviewed article published by Firenze University Press (http://www.fupress.net/index.php/ahs/) and distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability Statement: All relevant data are within the paper and its Supporting Information files. Competing Interests: The authors declare no competing interests. Received for publication 16 January 2024 Accepted for publication 31 January 2024 AHS Advances in Horticultural Science https://doi.org/10.36253/ahsc-15691 http://www.fupress.net/index.php/ahs/ http://creativecommons.org/licenses/by/4.0/ http://creativecommons.org/licenses/by/4.0/ http://creativecommons.org/licenses/by/4.0/ Adv. Hort. Sci., 2024 38(2): 155­167 156 Prajapati et al., 2021 a). The production volume in the Philippines has increased by 1.8% to 32.05 thousand metric tons (PSA, 2022). Its primary demand arises from its anti­diabetic properties (Rosario and Macusi, 2009). The presence of phenols, terpenes, and flavonoids in bitter gourd contributes to its bitter taste and antioxidant properties (Dutta et al., 2021), which are desired by consumers (Behera et al., 2010; Taiti et al., 2017) and can help prolong its shelf­life (Salas et al., 2015). The metabolites found in bitter gourd are affected by cultivars and cultural practices such as Light, temperature, soil, and nutrition (Valyaie et al., 2021). The importance of Light in postharvest produce cannot be overstated, as plants perceive stimulus for growth and development through light. Recent studies have discovered that even after plants are harvested, their light­dependent processes continue. To ensure the longevity of postharvest fruits and vegetables and maintain their metabolite levels, various treatments ­ both chemical and non­chemical ­ can be applied. For example, bittergourd fruits can be stored for up to five days under ambient conditions without ripening, yellowing, or losing their bitterness (Salas et al., 2015; Prajapati et al. , 2021 a). As a means of preserving postharvest produce, researchers have begun exploring the use of Light Emitting Diodes (LEDs). In fact, supplemental lighting from LEDs has been shown to enhance the market value of harvested sweet peppers by inducing colour break (Jones, 2018). Researchers have therefore explored the use of Light Emitting Diodes (LEDs) to prolong shelf­life and maintain metabolites in various crops (Ma et al., 2014; D’Souza et al., 2015; Bantis et al., 2018; Loi et al., 2020; Poonia et al., 2022). The findings of these studies have been corroborated by the upregulation of vitamin C, antioxidants, anthocyanins, and the physical appearance of fresh produce towards market acceptability. For example, white LED lighting facilitates the accumulation of phenols in harvested vegetables (Poonia et al., 2022), which are known to have antioxidant and anti­inflammatory properties and may enhance the health benefits of these crops. It was observed that the LEDs had a drying effect, leading to a rapid increase in transpiration, as reported by Chua et al. (2021). Various studies have shown that different types of light can have varying effects on different types of vegetables. For example, white and blue LEDs can modulate the stomata opening and number of stomates (Zhan et al., 2013), resulting in weight loss of certain vegetables such as Brassica oleracea L. var. italica Plenck (Favre et al., 2018), Brassica oleracea var. chinensis Lei (Zhou et al., 2020), and freshly­cut leaves of Amaranthus dubius L. (Jin et al., 2021). On the other hand, dark­ stored celery has a lower dry matter content compared to fresh­cut celery due to lower total soluble solids, ascorbic acid, and chlorophylls (Zhan et al., 2013; Florkowski et al., 2014). In another study, freshly sliced cherry tomatoes exposed to white, blue, and green LEDs showed a transitory increase in vitamin C one day after slicing, while those exposed to red light remained stable (Kong et al., 2020). It is worth noting that the effect of LED lighting on postharvest crops varies depending on the type of crop, LED intensity, and duration of exposure. For example, in previous studies, broccoli exposed to 9.5 and 19.0 W m­2 white LED illumination for three hours per day showed delayed chlorophyll degradation and lower weight loss (Pintos et al., 2020). Okra fruits treated with white and blue LEDs (17.28 W m­2) for 8 h showed an increased total phenolics content (Thilini Deepashika Perera et al., 2022), while berry grape treated with 41 and 42 W m­2 of LED showed an increased anthocyanin content at 24 h, and blue LED decreased fungal infections in citrus fruits at a fluence rate of 120 W m−2 and 700 W m­2 for 18 h under 25°C (Nassarawa et al., 2020). In addition, bitter gourd exposed to UV­C LED for 40 min at 10°C and 85­95% RH had a prolonged shelf­life of up to 16 d (Prajapati et al. , 2021 b). While chemical­based treatments have been the focus of many researchers to improve the postharvest life of vegetables, there is a growing interest in using LED treatments to increase shelf­life and enhance metabolites. It is hypothesized that varying illuminations of white, blue, and red LED with 1.5 Wattage (W) can delay pigmental degradation, preserve organic compounds, and extend shelf­life in harvested bitter gourd. This study tried to assess how the quality of bitter gourd change during post­ harvest by applying varying illuminations color LED (white, blue, and red) with 1.5 Wattage (W). 2. Materials and Methods Fruit samples and sample preparation The cultural practices and harvesting process of sixty bitter gourds from a commercial vegetable farm Ponteras et al. ‐ Postharvest bittergourd as influenced by illumination colors 157 in Barangay Buenavista, Baybay City, Leyte (lat. 10° 39’ 34.0” N, long. 124° 50’ 27.6” E) are described in this study. Organic and inorganic fertilizers were applied, including chicken dung through the basal method and soil drenching for urea and complete fertilizers during the vegetative and reproductive stages. The fruits, weighing 300­400 g and measuring 25 x 5 cm, were harvested at the dark green stage and were carried out carefully to minimize mechanical injuries. Fruits with defects were excluded from the study. The farmer­harvester, an expert in harvesting, chose the fruits for marketing based on the local market standard from the City mentioned above. The fruits were then transported from the farm to the Department of Horticulture Crop Physiology Laboratory for postharvest assessment from October 28 to November 03, 2022. The shelf­life of the fruits was 5 days (d), and the treatment application was done after 24 hours (h) to acclimatize and equilibrate the fruits at ambient conditions. The amount and time of fertilizer application were not included in the present study, as it was based on the farmer’s feedback during the harvest since the study utilized fruits from the farm instead of from the wet market. Treatment preparation The cardboard boxes with aluminum foil were arranged on the surface and equipped with 1.5 W/135 lumens (Foshan Electrical and Lighting Co., Ltd [FSL], China) LED lights, measuring 56 [L] x 45 [W] x 24 [H] cm. The LED source was positioned at a distance of 19 cm from the fruits. In the current study, each treatment was subjected to white, blue, and red LEDs for a duration of 4 h, with five (5) fruit samples per treatment. After incubation, the lights inside each cardboard box were switched off. However, the irradiated fruit samples were transferred and placed in plastic trays (40 × 30 cm) under ambient conditions (26­28°C). Each tray represented a replicate exposed to lights that remained switched on continuously for 8 h daily, including non­incubated fruit samples for storage and postharvest evaluation. Enhanced and stable metabolites were demonstrated during storage, resulting in a prolonged shelf­life from exposure to UV­C LED for 40 minutes (min), blue and red LEDs for 24 h, white and blue light for 8 h, and white LED for 3 h daily, as shown in previous studies (Nassarawa et al., 2020; Pintos et al., 2020; Prajapati et al., 2021 b; Thilini Deepashika Perera et al., 2022). Experimental design In a completely randomized design (CRD), the study had five samples per treatment replicated three times. The treatments were designated as follows: T1 ­ Control (Room light condition), T2 ­ Incubated 4 h with white LED at 1.5 Watt/135 lumen (FSL, China), T3 ­ Incubated 4 h with blue LED at 1.5 Watt/135 lumen (FSL, China), T4 ­ Incubated 4 h with red LED at 1.5 Watt/135 lumen (FSL, China). Data collection Physico‐chemical parameters. The fruits were assessed before and after gathering using a digital weighing scale (General Master, Japan), with the parameters being determined for each fruit from the five samples in replication manually every day for six days using different indices. The cumulative weight loss from the five samples from each replication was determined by weighing the initial weight and daily as known storage period (Prajapati et al., 2021 b). The fruit shrivelling index was assessed with slight modifications (Benitez et al., 2015; Lualhati and Del Carmen, 2018) using a 4­point scale ranging from 1 to 4 (where 1 indicated no shrivelling, 2 indicated slight shrivelling (1­25% fruit surface affected), 3 indicated moderate shrivelling (26­50% fruit surface affected), and 4 indicated severe shrivelling (more than 50% fruit surface affected). The visual quality rating (VQR) of Bitter gourd was evaluated daily as reported by Valida et al. (2018). In brief, VQR was assessed using a 9­point scale, where 9 indicated excellent, field fresh or no defects, 7 indicated good, defects minor, 5 indicated fair, defects moderate, limit of marketability, 3 indicated poor, defects serious, l imit of edibility, and 1 indicated non­edible under usual condition. The degree of yellowing was rated manually daily as reported by Valida et al. (2018) using a 5­point scale, where 1 indicated full green, 2 indicated 1­10% surface yellowing, 3 indicated 11­30% surface yellowing, 4 indicated 31­50% surface yellowing, and 5 indicated extensive yellowing/discoloration. The dry matter content (%) was determined by subjecting the samples (50 g) to oven drying at 70°C for 24 h until they reached a constant weight. The remaining weight of the samples after drying served Adv. Hort. Sci., 2024 38(2): 155­167 158 as input to calculate the percent dry matter content as a percentage of the wet sample (Gonzales and Benitez, 2019). The pigment composition (mg g­1) was determined by soaking a gram of each representative bitter gourd fruit in 10 ml of 95% ethanol overnight. The absorbance of the filtrates at wavelengths of 666, 653, and 470 nm was measured using an ultraviolet­ visible spectrophotometer at the VSU­CASL (Salas et al., 2020). The shelf life was determined when sample fruits reached a VQR of 5, which is fair with moderate defects and limited marketability (Salas et al., 2015; Valida et al., 2018). Chemical Parameters. For the examination of chemical parameters, one fruit from each replication was randomly selected as a representative. The protocol appears to have been based on the report of Gonzales and Benitez (2019) and Salas et al. (2020). The fresh­cut samples were homogenized in 10 g per 50 ml distilled water for 10 min using a homemade blender (CAMEL®), and the filtrates were measured for potential hydrogen (pH), electrical conductivity (EC) and total dissolved solids (TDS) using a smart combined meter (Milwaukee, MW 802) Total soluble solid (°Brix) was measured using a hand­held refractometer (Atago N1, Japan) by placing 1­3 drops of juice on the instrument prism and taking the reading. Titrable acidity (%) was determined by adding 5 ml extract with two drops of 1% phenolphthalein indicator into a volumetric flask containing 4 g NaOH diluted with 1 L distilled water, followed by titration with 0.1% NaOH until a faint pink colour was obtained. Finally, for Vitamin C analysis (mg 100 g fresh fruit­1), fresh cut (12 g) was subjected to 5 min with 120 ml distilled water in a blender until supernatant filtered. An aliquot (1 ml) extract was mixed in a 125 ml Erlenmeyer flask containing 50 ml distilled water and three drops of starch solution as an indicator. Iodometric titration and volumetric techniques were employed for the analysis. Statistical analysis After the analysis of variance (ANOVA) was conducted, the treatment mean was compared and separated by the Honest Significant Difference (HSD) using the Statistical Tool for Agricultural Research (STAR) program, which had been developed by the International Rice Research Institute (IRRI). 3. Results and Discussion Fruit shriveling Table 1 shows a gradually increasing index of bitter gourd fruit shriveling. At 3 days (d), delayed shriveling for those fruits with white and blue light treatments. Consequently, shriveling was slight to moderate until 6 d of storage. Endalew (2020) states that shriveled fruit reduces consumer acceptability and marketability. During the transport, the cushioning materials such as newspaper, foam nets, leaves, and other local materials then packed in cardboard boxes or plastic trays could help prevent fruits from bruising and touching, which leads to morpho­physiological disorder and increased entropy (Ahmad and Siddiqui, 2015; Valida et al., 2018; Hussein et al., 2020). Table 1 ­ Fruit shrivelling of bittergourd as influenced by illumination colors during storage Data represent mean ± deviation standard. Mean values (n = 5) from three replicates in each column of sampling times followed by different letters are significantly different from each other at 5% Tukey’s test. NS= not significant. CV= Coefficient of variation. Treatments Fruit shrivelling 2 d 3 d 4 d 5 d 6 d Control (No LEDs) 1.00±0.00 NS 1.06±0.12 ab 1.78±0.57 NS 2.42±0.24 NS 2.72±0.05 NS White LEDs 1.00±0.00 NS 1.00±0.00 b 1.27±0.12 NS 2.40±0.40 NS 2.60±0.35 NS Blue LEDs 1.00±0.00 NS 1.00±0.00 b 1.33±0.42 NS 2.40±0.40 NS 2.78±0.71 NS Red LEDs 1.00±0.00 NS 1.21±0.03 a 1.50±0.30 NS 2.33±0.42 NS 3.13±0.23 NS CV (%) 0.00 5.56 26.28 15.51 14.74 Ponteras et al. ‐ Postharvest bittergourd as influenced by illumination colors 159 Yellowing index Bitter gourd is a climacteric fruit that ripens and turns yellow during storage due to ethylene production (Yahia et al., 2019). As shown in Table 2, there is a 1­10% (YI=2) yellowing after the third. Fruits exposed to white LEDs (WL) and Blue LEDs (BL) maintained the greenness at 3 d of storage but compared to control. As the days passed until 6 d, the yellowing progressed to 11­30% (YI=3), and the quality began deteriorating. Several factors, including senescence, free radicals, energy, metal ions, and some secondary metabolites in fruits and vegetables, can cause postharvest yellowing (Luo et al., 2019). Diaz et al. (2006) observed that chlorophyll degradation and anthocyanin accumulation cause the yellowing of Arabidopsis thaliana leaves. According to other studies, light treatment prevents some fruit postharvest problems, for example: (a) the use of Red LED light delays yellowing and reduces ethylene production in broccoli inflorescences (Ma et al., 2014); (b) white and Blue LEDs of 20 molm­2 s­1 controls yellowing and maintains the green color of the outer and inner leaves of Brussels sprouts during storage (Hasperué et al., 2016); (c) artificial lighting modulates stomata opening in green tissues keeps fruits from dehydration and delays degreening by delaying cell aging and disorganization (Pintos et al., 2020); (d) continuous exposure to white and blue LEDs under 5 and 22°C results to have higher chlorophylls a and b which remains stable and green during storage (Hasperué et al., 2016 a, b). It is in line with the findings of Loi et al. (2019), which the broccoli heads increased the chlorophylls resulted from metabolic activity exposed with BL, 467 nm, 4.1 W/m and WL, 31 lm/W. Visual quality rating In the selection of fruits and vegetables, visual characteristics are frequently used by consumers. Visual quality loss with moderate defects after 5 d of storage was delayed by white and blue light, as shown in Table 3. Poor quality with serious defects was observed in those fruits without LED and red LED Table 2 ­ Yellowing index of bittergourd as influenced by illumination colors during storage Data represent mean ± deviation standard. Mean values (n = 5) from three replicates in each column of sampling times followed by different letters are significantly different from each other at 5% Tukey’s test;NS= not significant. CV= Coefficient of variation. Treatments Yellowing Index 2 d 3 d 4 d 5 d 6 d Control (No LEDs) 1.00±0.00 NS 1.06±0.12 ab 1.91±0.38 NS 3.14±0.43 NS 3.33±0.76 NS White LEDs 1.00±0.00 NS 1.00±0.00 b 1.40±0.40 NS 2.45±0.40 NS 3.01±0.52 NS Blue LEDs 1.00±0.00 NS 1.13±0.12 ab 1.64±0.34 NS 2.75±0.43 NS 3.03±0.29 NS Red LEDs 1.00±0.00 NS 1.28±0.10 a 1.98±0.23 NS 2.83±0.76 NS 3.50±0.50 NS CV (%) 0.00 8.64 19.70 18.86 16.91 Table 3 ­ Visual quality rating of bittergourd as influenced by illumination colors during storage. Data represent mean ± deviation stan­ dard Data represent mean ± deviation standard. Mean values (n = 5) from three replicates in each column of sampling times followed by different letters are significantly different from each other at 5% Tukey’s test; NS= not significant. CV= Coefficient of variation. Treatments Visual quality rating 2 d 3 d 4 d 5 d 6 d Control (No LEDs) 9.00±0.00 NS 7.84±0.73 NS 6.18±0.84 NS 3.85±0.13 b 3.06±0.82 NS White LEDs 9.00±0.00 NS 8.73±0.23 NS 6.47±0.61 NS 6.24±0.80 a 4.13±0.81 NS Blue LEDs 9.00±0.00 NS 8.73±0.46 NS 6.53±0.50 NS 5.50±0.87 ab 3.97±0.29 NS Red LEDs 9.00±0.00 NS 8.00±0.20 NS 5.93±0.31 NS 3.71±0.92 b 3.28±1.49 NS CV (%) 0.00 5.52 9.48 15.55 26.45 160 Adv. Hort. Sci., 2024 38(2): 155­167 treatments, leaving them unfit for consumption (Fig. 1). The deterioration of visual quality over time following harvest has been observed in various studies. However, the visual appearance and shelf life of fresh produce can be improved by postharvest lighting using LEDs. The effect of white­blue LEDs on the outer and inner leaves of Brussels sprouts during a 10 d storage period at 22°C was investigated. Lower respiration rates and better visual quality were found than in the controls (Poonia et al., 2022). The levels of vitamin C (35 mg 100 g FW­1) and soluble carbohydrates (8.3 mg g FW­1 sucrose on the fourth day) in fresh­cut lettuce were increased by postharvest lighting. On the initial day, light at 50 % falls to 15 mg 100 g FW­1 vitamin C and 0.2 mg g FW­1 sucrose, respectively (Witkowska, 2013). The observed improved visual appearance and, eventually, longer shelf life can be attributed to this (Bantis et al., 2018). As demonstrated by freshly cut leaves amaranth, photosynthesis is unsustainable with insufficient light intensity (Jin et al., 2021). As a signal driving this process, the conversion of sugars via gluconeogenesis is driven by low irradiance, producing glucose through the TCA cycle (Wolter and Seifu, 2015). Fresh­cut celery had a higher total dissolved solids than dark­stored celery (Zhan et al., 2013). It indicates that photosynthesis continued functioning, allowing postharvest crops to remain viable. Because stored organic acids such as malic and citric are undissociated from the vacuoles, preservation of titratable acidity is a good indicator of fruit quality, reflecting shelf­life (Utama et al., 2022). Furthermore, the activity of polyphenol oxidase, responsible for cell integrity breakdown, can be inhibited by ascorbate, making it a universal antioxidant that can help preserve the freshness of fruits and vegetables (Toivonen and Brummell, 2008). Weight loss (%) In Table 4, weight loss (%) is shown in increasing order. The acceptable limit (1­11%) for bitter gourd is observed in the present findings; if it exceeds, it leads to severe fruit shriveling and undesirability (Lualhati and Del Carmen, 2018). As a result, significant weight loss after three days of storage is prevented in bitter Fig. 1 ­ A visual quality rating (VQR) of bitter gourd fruit ‘Jadeite’ cultivar at 5th day of storage. (A) T1­ Control (No LEDs), the fruits were poor with serious defects and limit edibili­ ty; (B) T2­ White LEDs, the fruits were good with minor defects; (C) T3­ Blue LEDs, the fruits were fair with mod­ erate defects and limit marketability; (D) T4­ Red L E D s , the fruits were poor with serious defects and limit edibili­ ty. Table 4 ­ Weight loss (%) and dry matter content (%) of bittergourd as influenced by illumination colors during storage Data represent mean ± deviation standard. Mean values (n = 5) from three replicates in each column of sampling times followed by different letters are significantly different from each other at 5% Tukey’s test; NS= not significant. CV= Coefficient of variation. Treatments Weight loss (%) Dry matter content (%)3 d 4 d 5 d 6 d Control (No LEDs) 1.95±0.23 ab 4.48±0.68 NS 7.42±1.23 NS 11.41±1.42 NS 20.87±0.64 b White LEDs 1.58±0.12 b 4.04±0.19 NS 6.52±0.08 NS 9.99±0.17 NS 20.67±0.31 b Blue LEDs 2.15±0.20 a 4.64±0.39 NS 7.46±0.78 NS 11.26±1.11 NS 21.40±1.31 b Red LEDs 1.88±0.12 ab 4.83±0.49 NS 7.79±0.80 NS 12.17±0.77 NS 20.47±0.46 b Initial data ­ ­ ­ ­ 26.00±0.00 a CV (%) 9.08 10.44 11.39 8.77 3.19 Ponteras et al. ‐ Postharvest bittergourd as influenced by illumination colors 161 gourd treated with white and red light. The findings are consistent with Li’s (2016) study on strawberries, which found that fruits illuminated with blue light lost more weight than fruits in white and dark treatments due to increased calyx transpiration under blue light. Bitter gourd wilts and shrivels due to weight loss, which lowers its market value and consumer acceptability (Prajapati, 2021 a). Furthermore, shelf life is extended by slowing the water absorption rate, as with pepper (Wills et al., 1998). Weight loss in fresh produce is caused by water loss due to transpiration and respiration (Zhu et al., 2008). Throughout the storage period, the percentage of weight loss increases. Typically, weight loss during fruit storage results from the respiratory process, humidity transfer, and some oxidation processes (Ayranci and Tunc, 2003). Quality parameters were preserved, and storage was prolonged from 15 to 20 d by treating bitter gourd fruits with 100 mmol L­1 /mM Calcium lactate (CL) at 10°C and 85­95 % RH, 1­MCP, edible coating with carnauba wax (1.0 %), UV­C LED 40 min, modified atmospheric packaging using LDPE (100 microns) (Prajapati et al., 2021 b). The enhanced membrane integrity was due to calcium stabilizing the cell membrane and turgor pressure. In UV­C LED exposure, the epicuticular wax morphology changed by reducing microcrystalline structure, which gave a better protective layer and thus reduced weight loss (Prajapati et al., 2021 a). Dry matter content (%) The data presented in Table 4 clearly demonstrate an inverse relationship between the moisture content and dry matter content of eggplant, both during storage and after harvest. The high respiration rate of eggplant fruit results in high water loss and low dry matter content, which can lead to shrivelling and reduced consumer acceptability, unless proper postharvest treatments are applied. In this regard, fruits treated with 1% Alginate and lacking an edible coating showed a lower dry matter content on the initial day, decreasing from 8.4% to 7.5%. Despite the positive results reported by Huang et al. (2017) on the dry biomass of oyster mushrooms under blue LED light, our study found that the dry matter content was unaffected by this type of light. Ripening is a complex process that involves the accumulation of various metabolites, such as carbohydrates, sugars, vitamins, and other compounds, which contribute to the dry matter content and the conversion into other products. The fresh­cut celery treated with LEDs revealed a higher dry matter content than dark­stored celery, due to the higher levels of total soluble solids, ascorbic acid, and chlorophylls, as reported by Zhan et al. (2013) and Florkowski et al. (2014). Finally, the results are consistent with those of Bantis et al. (2018), who found that high levels of blue LED light exposure can increase the dry matter content and enhance radical scavengers and soluble sugars in mushrooms, thanks to the higher metabolic activity in synthesizing other products as a result of respiration. Pigmental composition (mg g‐1) Bittergourd fruits before treatment contained chlorophyll a (6.57 mg g­1), b (3.61 mg g­1), and total (10.19 mg g­1), respectively. Table 5 shows that the fruits at 5 d storage had maintaining levels of pigments but were degrading. Fruits exposed to Data represent mean ± deviation standard. Mean values (n = 5) from three replicates in each column of sampling times followed by different letters are significantly different from each other at 5% Tukey’s test; NS= not significant. CV= Coefficient of variation. Table 5 ­ Pigmental composition (mg g­1) and shelf­life (d) of bittergourd as influenced by illumination colors during storage Treatments Chlorophyll and carotenoid contents (mg g­1) Shelf­life (d) Chl a Chl b T Chl T CarNS Control (No LEDs) 3.06±0.36 b 1.58±0.35 b 4.65±0.71 b 1.80±0.34 NS 4.67±0.58 NS White LEDs 5.66±2.01 ab 2.64±1.08 ab 8.30±3.07 ab 2.53±0.58 NS 5.00±0.10 NS Blue LEDs 4.91±1.21 ab 2.34±0.55 ab 7.25±1.75 ab 1.95±0.51 NS 5.33±0.58 NS Red LEDs 4.56±0.85 ab 2.20±0.27 ab 6.76±1.16 ab 1.99±0.24 NS 4.67±0.58 NS Initial data 6.57±0.00 a 3.61±0.00 a 10.19±0.00 a 2.48±0.00 NS ­ CV (%) 22.73 23.28 22.71 18.15 14.38 Adv. Hort. Sci., 2024 38(2): 155­167 162 white, blue, and red LEDs had better pigmental composition than those exposed to control. Between the two pigments, chlorophyll a contained higher levels than chlorophyll b, resulting in reduced amounts during storage. It agrees with Prajapati et al. (2021 a), who found that total chlorophyll decreased with storage treatments. This event is considered a tug­of­war between two pigments during the yellowing process. High chlorophyll is sought after by consumers. The chlorophyll content decreased when the broccoli started yellowing (Loi et al., 2019). In contrast, there were carotenoid and chlorophyll syntheses in Brussels sprouts under low light intensity using WB LED for 10 d. However, photooxidation will destroy the carotenoid at higher light intensity (Hasperué et al., 2016). The delayed decline of carotenoid contents was due to exposure to white LED at 1.4 W m−2 for 8 d (Nassarawa et al., 2020). The carotenoid primary function is to act as an accessory light­harvesting system, which aids in light absorption. It is considered to be photoprotective by inhibiting free radicals in chloroplasts (Jones, 2018; Salas et al., 2019). It acts as an antioxidant by donating hydrogen to neutralize singlet oxygen (Gorni et al., 2021). The phytochrome family perceives red light between 600 and 750 nm. At the same time, the blue light (320­500 nm) spectrum includes cryptochromes and phototropins under the ZEITLUPE/ADAGIO family. Similarly, the stability of Cryptochrome Circadian Regulator 1 (CRY1) depends on the il lumination, but the Cryptochrome Circadian Regulator 2 (CRY2) receptor breaks after light exposure (Jones, 2018). Although Red LEDs (RL) did not induce chlorophyll accumulation, when combined with Blue LEDs (BL), the chlorophyll content of a non­heading Chinese cabbage increased (Fan et al., 2013; Bantis et al. 2018). LED illumination improved crop pigmental composition while lowering reactive oxygen species activity (Kong et al., 2020; Loi et al., 2020). The green pigments found in fresh vegetables and fruits originated from chlorophyll in the chloroplast, which would then destroy PSII by decreasing the chlorophyll contents during yellowing (Luo et al. , 2019). Both chl a and chl b have collaborated to widen the light spectrum associated with photoreceptors to harvest light emissions (Salas et al., 2019). Before yellowing, NYC1 levels increased, but after 5 d of storage, they decreased (Luo et al., 2019). The intensity of RL at 50 molm­2 s­1 increased the carotenoid content of Satsuma mandarin after 6 d of storage. At the same time, BL did not improve carotenoid accumulation (Ma et al., 2014; Bantis et al., 2018). Shelf‐life It was found that the use of different illuminations did not have a significant impact on the shelf life of bitter gourd, as per the study that was discussed (Table 5). Regardless of whether LEDs were used or not, the fruits were only lasting for around 4­5 d during storage (Salas et al., 2015). However, it was suggested that future research could explore the possibility of increasing LED duration and lowering temperatures in order to prolong the shelf life of bitter gourd. It was noted that fruits are generally highly perishable when stored at room temperature, which can result in significant postharvest losses (Pott et al., 2020). As such, extending the shelf life of such crops can be considered a significant breakthrough in research. Bitter gourd, in particular, degrades quite rapidly due to various factors, such as the presence of protruding ridges, excessive seed development, tissue softening, yellowing, and ripening, which can make it challenging to market (Prajapati et al., 2021 b). Previous studies have shown that LEDs can have a positive impact on the metabolites and postharvest life of various crops, including bitter gourd. For example, it was found that the shelf life of crops like M. charantia (Prajapati et al., 2021 a), Brassica oleracea L. var. Italica (Loi et al., 2019), and broccoli (Hasperue et al., 2016; Pintos et al., 2020) was prolonged significantly when exposed to certain types of LEDs. It was found that the study did not yield significant results on the shelf­life of bitter gourd. However, as argued by D’Souza et al. (2015), the shelf­life and quality of horticultural products can be influenced by postharvest light through the potential increase of soluble carbohydrates, which serve as the substrate for respiration during postharvest storage, and through the enhancement or preservation of visual appeal through pigment accumulation, such as lycopene, carotenoids, and anthocyanins. Significant potential has been demonstrated by LED technology for promoting the growth and synthesis of beneficial compounds and extending the shelf­life of fruits and vegetables during postharvest storage, as reported by Loi et al. (2020). It was observed that fruits did not experience any prevention from shrivelling, Ponteras et al. ‐ Postharvest bittergourd as influenced by illumination colors 163 yellowing, and weight loss when exposed to blue and red LED. Additionally, there was no influence on visual quality with red LED on the fifth day. However, an increased content of total chlorophyll, vitamin C, pH, and total phenolics in cabbage was observed when exposed to continuous lights using white, blue, green, and red LEDs. Green tomatoes’ delayed ripening and softening resulted from exposure to blue and red LEDs for 21 d, while an increase in contents of sugars, chlorophyll, and carotenoids in broccoli at 5°C and 22°C was observed when exposed to white and blue LED with a fluence rate of 20 W m−2 (reviewed by Nassarawa et al., 2020). Chemical parameters Fruit cell walls containing polysaccharides solubilized and hydrolyzed into simple sugars, which gives rise to the soluble solids (Ayu et al., 2020; Mirshekari et al., 2020; Suriati et al., 2022) and are affected by room temperature (Mutua et al., 2021). However, the decrease in soluble solids resulted from respiration during fruit storage (De Paula et al., 2020). The enhanced shelf­life of fruits indicates slow utilization of soluble solids (Nassarawa et al., 2020). One of the critical metabolites is Vitamin C, an antioxidant against free radicals and a nutrient source in fruits and vegetables (Loi et al., 2019; Mirshekari et al., 2020). As a precursor, glucose synthesis is necessary for synthesizing vitamin C via the L­ galactose pathway and D­galacturonic acid (Fernandez and De Guzman, 2022). Using organic acids in respiration increases pH over storage (Gonzales and Benitez, 2019). The increase in pH values was concomitant with a reduction in Vitamin C and TA, which concurs with Salas et al. (2020). Cucumber’s shelf life has been extended due to the preservation of TA over time (Zapata et al. 2008, as cited by Gonzales and Benitez 2019). Based on the study results, the electrical conductivity (EC) increased with storage time. Conforming to the Salas et al. (2020) study, eggplant fruits with a high amount of electrolytes deteriorate quickly. This is due to the gradual breakdown of cell membrane integrity mediated by lower lipoxygenase (Cai et al., 2006), resulting in ion imbalance and electrolyte leakage as well as excessive shriveling and softening (Tesfay and Magwaza, 2017; Cheema et al., 2018). Table 6 shows significant results in bitter gourd chemical characteristics such as pH and TA as influenced by the varying illumination. However, the result of this study yielded insignificance in terms of EC, TDS, TSS, and Vitamin C. It agrees with the findings of D’Souza et al. (2015) that the white LED (500­700 nm) imposed did not influence the ascorbate production. It can deduced that light treatments with 1.5 W in 4 h have insufficient doses to bring significant improvement in the said metabolite. Exposure to continuous white and blue LEDs resulted in a slight increase in ascorbic acid (Asc) content at the end of broccoli storage (Hasperué et al., 2016). Sweet peppers with Blue light at 450 nm in 8 h per day had minimum changes in ascorbic acid content (Thilini Deepashika Perera et al., 2022). Blue LED at a lower intensity, 20 μmol m−2 s−1 under 5°C, decreased the Asc content of broccoli while maintaining the levels at a higher intensity, 50 μmol m−2 s−1 (Loi et al., 2019). Red, blue, and green lights at 20, 40, and 60 W m−2 increased the TSS of Table 6 ­ Chemical parameters of bittergourd as influenced by illumination colors during storage. Data represent mean ± deviation stan­ dard Data represent mean ± deviation standard. Mean values (n = 5) from three replicates in each column of sampling times followed by different letters are significantly different from each other at 5% Tukey’s test; NS= not significant. CV= Coefficient of variation. Treatments Chemical parameters pH value EC mS TDS ppm TSS °brix TA % Vit. C mg 100 g­1 Control (No LEDs) 7.83±0.06 a 3.12±0.25 NS 2153.33±142.24 NS 1.83±0.14 NS 0.49±0.11 b 0.14±0.02 NS White LEDs 7.73±0.12 a 3.26±0.55 NS 2233.33±390.68 NS 1.92±0.14 NS 0.38±0.08 b 0.12±0.04 NS Blue LEDs 7.16±0.12 b 3.05±0.18 NS 2086.67±128.97 NS 1.83±0.14 NS 0.47±0.14 b 0.18±0.03 NS Red LEDs 7.16±0.06 b 2.94±0.53 NS 2013.33±355.29 NS 1.75±0.25 NS 0.47±0.07 b 0.19±0.05 NS Initial data 4.60±0.00 c 2.40±0.00 NS 1640.00±0.00 NS 2.00±0.00 NS 0.86±0.00 a 0.18±0.00 NS CV (%) 1.18 12.49 12.41 8.47 17.34 19.98 Adv. Hort. Sci., 2024 38(2): 155­167 164 fruits (Nassarawa et al., 2020). A single application of RL to harvested vegetables increased the sugar, soluble protein, and vitamin C content (Loi et al., 2020; Poonia et al., 2022). Bitter gourd has a low TSS (°brix) compared to other fruits with high sugar content, such as pitaya, which contains several monosaccharides that contribute to sweetness. In addition, the sugar content of the skin of grape berries was enhanced after red and blue light exposure at 50 μmol m−2 s−1 (D’Souza et al., 2015). Cell wall breakdown and postharvest decay were delayed by blue light emission within 2 h at 25°C, which decreased monosaccharides such as glucuronic acid in pitaya fruits (Pott et al., 2020). 4. Conclusions The current study aimed to investigate the effects of white, blue and red Light Emitting Diodes (LEDs) on the pigment composition, physical and chemical parameters of bittergourd (Momordica charantia L.). Irradiated and non­irradiated fruit samples were at ambient temperature with an 8 h continuous light source from the room ceiling. Based on the present findings, the white and blue LEDs delayed fruit shrivelling and yellowing on the third day and maintained an excellent visual appearance on the fifth day compared to the control and red LEDs. White LEDs had lower weight loss, followed by red and no LEDs on the third day. Among the treatments, the dry matter content decreased from the initial day. The white, blue, and red LEDs did not prevent fruits from yellowing, but there was a slight change compared to the control with the lowest amount of total chlorophyll a and b, whereas the carotenoids remained stable. Regardless of treatments, the pH values (neutral) increased from the initial day (acidic). However, the blue and red LEDs had lower pH values compared to white and control. Irrespective of treatments, the EC, TDS, and vitamin C remained stable during storage. In contrast, TA lowered from the initial day. White and blue reached a shelf­life of 5 d, whereas red LED and control until four days, numerically. Generally, LEDs with 1.5 W had the potential to improve the quality and shelf­life of bitter gourd fruits. Among the treatments, the white LED positively affected the physical and chemical parameters. Increasing the wattages or light intensities under continuous or intermittent lighting with lower temperatures makes it possible to achieve preserved fruit quality beyond five days of shelf­life. Based on the results, it would suggests potentiality of LEDs for the future studies, which can be a useful information towards preserving the physico­chemical attributes of bittergourd and other postharvest crops. Acknowledgements The authors would like to acknowledge the support of the Commission of Higher Education (CHED) Region VIII, Tacloban City, Leyte, for a scholarship and the Department of Horticulture and Office of the Graduate School of the Visayas State University, Visca, Baybay City, Leyte, Philippines, for the laboratory tools. References AHMAD M.S., SIDDIQUI M.W., 2015 ­ Factors affecting postharvest quality of fresh fruits, 7­32. ­ In: AHMAD M.S., and M.W. SIDDIQUI Postharvest quality assurance of fruits. Springer, Cham, Switzerland, pp. 285. AYRANCI E., TUNC S., 2003 ­ A method for the measurement of the oxygen permeability and the development of edible films to reduce the rate of oxidative reactions in fresh foods. ­ Food Chem., 80: 423­431. AYU D.F., RUMENGAN O.S., PATO U., 2020 ­ Combination of pineapple and okra on chemical and sensory characteristics of fruit leather. ­ IOP Conf. Series: Earth Environ. Sci., 515: 012049. BANTIS F., SMIRNAKOU S., OUZOUNIS T., KOUKOUNARAS A., NTAGKAS N., RADOGLOU K., 2018 ­ Current status and recent achievements in the field of horticulture with the use of light‐emitting diodes (LEDs). ­ Sci. Hortic., 235: 437­451. BEHERA T.K., BEHERA S., BHARATHI L.K., JOHN K.J., SIMON P.W., STAUB J., 2010 ­ Bitter gourd: Botany, horticulture, breeding. ­ Hort. Rev., 37: 101­141. BENITEZ M.M., ZAPANTA R.J.S., BRIONES E.D., 2015 ­ Postharvest quality and antioxidant content of organic eggplant (Solanum melongena L.) in modified atmosphere packaging. ­ Acta Horticulturae, 1088: 261­ 266. CAI C., CHEN K., XU W., ZHANG W., LI X., FERGUSON I., 2006 ­ Effect of 1‐MCP on postharvest quality of loquat fruit. ­ Postharvest Biol. Techn., 40: 155­162. CHEEMA A., PADMANABHAN P., AMER A., PARRY M.J., LIM L.­T., SUBRAMANIAN J., PALIYATH G., 2018 ­ Ponteras et al. ‐ Postharvest bittergourd as influenced by illumination colors 165 Postharvest hexanal vapor treatment delays ripening and enhances shelf life of greenhouse grown sweet bell pepper (Capsicum annum L.). ­ Postharvest Biol. Techn., 136: 80­89. CHUA A., CHONG L., GHATE V., YUK H.­G., ZHOU W., 2021 ­ Antifungal action of 405 nm light emitting diodes on tomatoes in a meso‐scale system and their effect on the physicochemical properties. ­ Postharvest Biol. Techn., 172: 111­366. D’SOUZA C., YUK H.­G., KHOO G.H., ZHOU W., 2015 ­ Application of light‐emitting diodes in food production, postharvest preservation, and microbiological food safety. ­ Comprehensive Rev. Food Sci. Food Safety, 14: 719­740. DE PAULA V.F.S., DE GÓES G.B., DE ARAÚJO N.O., NASCIMENTO I.B.D., DE MEDEIROS J.F., AROUCHA E.M.M., 2020 ­ Application of light‐emitting diodes in food production, postharvest preservation, and microbiological food safety.. ­ Adv. Hort. Sci., 34(2): 183­190. DHILLON N.P.S., SANGUANSIL S., SCHAFLEITNER R., WANG Y.­W., MCCREIGHT J.D., 2016 ­ Diversity among a wide Asian collection of bitter gourd landraces and their genetic relationships with commercial hybrid cultivars. ­ J. Am. Soc. Hort. Sci., 141: 475­484. DIAZ C., SALIBA­COLOMBANI V., LOUDET O., BELLUOMO P., MOREAU L., DANIEL­VEDELE F., MOROT­GAUDRY J.­ F., MASCLAUX­DAUBRESSE C., 2006 ­ Leaf yellowing and anthocyanin accumulation are two genetically independent strategies in response to nitrogen limitation in Arabidopsis thaliana. ­ Plant Cell Physiol., 47: 74­83. DUTTA S., HAZRA P., SAHA S., ACHARYA B., BHATTACHARJEE, T., MAURYA P.K., BANERJEE S., CHAKRABORTY I., CHATTOPADHYAY A., 2021 ­ Applied mutagenesis could improve economically important traits in bitter gourd (Momordica charantia L.). ­ J. Genet., 100: 43. ENDALEW, 2020 ­ Postharvest loss assessment of tomato (Lycopersicon esculentum Mill) (Galilea Cultivar) along the postharvest supply chain, northwest ethiopia. ­ Master’s Thesis, Bahir Dar University, Bahir Dar, Ethiopia. FAN X., ZANG J., XU Z., GUO S., JIAO X., LIU X., GAO Y., 2013 ­ Effects of different light quality on growth, chlorophyll concentration and chlorophyll biosynthesis precursors of non‐heading Chinese cabbage (Brassica campestris L.). ­ Acta Physiol. Plant., 35: 2721­2726. FAVRE N., BÁRCENA A., BAHIMA J.V., MARTÍNEZ G., COSTA L., 2018 ­ Pulses of low intensity light as promising technology to delay postharvest senescence of broccoli. ­ Postharvest Biol. Techn., 142: 107­114. FERNANDEZ A., DE GUZMAN C., 2022 ­ Influence of potassium fertilization on the functional components and antioxidant activity of pummelo [Citrus maxima (Burm. Ex Rumph.) Merr.] fruit. ­ Annals Tropical Res., 44(1): 17­29. FLORKOWSKI W.J., SHEWFELT R.L., BRUECKNER B., PRUSSIA S.E., 2014 ­ Postharvest Handling: A systems approach. ‐ Academic Press, London, UK, pp. 564. GONZALES L.M., BENITEZ M., 2019 ­ Polysaccharide‐based edible coatings improve eggplant quality in postharvest storage. ­ Sci. Humanities J., 13: 48­70. GORNI P.H., CORNELISSEN B. DA S., PEREIRA A.A., 2021 ­ Exogenous salicylic acid and ferulic acid improve growth, phenolic and carotenoid content in tomato. ­ Adv. Hort. Sci., 35: 335­341. HASPERUÉ J.H., GUARDIANELLI L., RODONI L.M., CHAVES A.R., MARTÍNEZ G.A., 2016 ­ Continuous white‐blue LED light exposition delays postharvest senescence of broccoli. ­ LWT ­ Food Sci. Techn., 65: 495­502. HASPERUÉ J.H., RODONI L.M., GUARDIANELLI L.M., CHAVES A.R., MARTÍNEZ G.A., 2016 ­ Use of LED light for Brussels sprouts postharvest conservation. ­ Scientia Hortic., 213: 281­286. HUANG M., LINK., LU C., CHEN L., HSIUNG T., CHANG W., 2017 ­ The intensity of blue light‐emitting diodes influences the antioxidant properties and sugar content of oyster mushrooms (Lentinus sajor­caju). ‐ Scientia Hortic., 218: 8­13. HUSSEIN Z., FAWOLE O.A., OPARA U.L., 2020 ­ Harvest and postharvest factors affecting bruise damage of fresh fruits. ­ Hort. Plant J., 6: 1­13. JIN S., DING Z., XIE J., 2021 ­ Study of postharvest quality and antioxidant capacity of freshly cut Amaranth after blue LED light treatment. ­ Plants, 10: 1614. JONES M.A., 2018 ­ Using light to improve commercial value. ­ Hortic. Res., 5. KONG D., ZHAO W., MA Y., LIANG H., ZHAO X., 2020 ­ Effects of light‐emitting diode illumination on the quality of fresh‐cut cherry tomatoes during refrigerated storage. ­ Inter. J. Food Sci. Techn., 56: 2041­2052. LI S., 2016 ­ The influence of postharvest light treatments on strawberries quality aspects. ­ MSc­Thesis, Wageningen University, The Netherlands. LOI M., LIUZZI V.C., FANELLI F., DE LEONARDIS S., MARIA CREANZA T., ANCONA N., PACIOLLA C., MULÈ G., 2019 ­ Effect of different light‐emitting diode (LED) irradiation on the shelf life and phytonutrient content of broccoli (Brassica oleracea L. var. italica). ­ Food Chem., 283: 206­214. LOI M., VILLANI A., PACIOLLA F., MULÈ G., PACIOLLA C., 2020 ­ Challenges and opportunities of light‐emitting diode (LED) as key to modulate antioxidant compounds in plants. A Review. ­ Antioxidants, 10: 42. LUALHATI R., DEL CARMEN D., 2018 ­ Cooling efficiency and effectiveness of single‐crate evaporative cooler for selected fresh produce. ­ The Philippine J. Crop Sci., 43: 47­55. LUO F., CAI J.­H., KONG X.­M., ZHOU Q., ZHOU X., ZHAO Y.­ B., JI S.­J., 2019 ­ Transcriptome profiling reveals the roles of pigment mechanisms in postharvest broccoli Adv. Hort. Sci., 2024 38(2): 155­167 166 yellowing. ­ Hort. Res., 6: 74. MA G., ZHANG L., SETIAWAN C.K., YAMAWAKI K., ASAI T., NISHIKAWA F., MAEZAWA S., SATO H., KANEMITSU N., KATO M., 2014 ­ Effect of red and blue LED light irradiation on ascorbate content and expression of genes related to ascorbate metabolism in postharvest broccoli. ­ Postharvest Biol. Techn., 94: 97­103. MIRSHEKARI A., MADANI B., WALL M.M., BIGGS A.R., 2020 ­ Aloe vera coatings maintain antioxidants of fig (Ficus carica L.) fruit during storage. ­ Adv. Hort. Sci., 34(2): 205­212. MUTUA C., OGWENO J.O., GESIMBA R.M., 2021 ­ Postharvest quality of pepino melon (Solanum muricatum Aiton) as influenced by NPK fertilizer rates, growing environment and storage temperature. ­ Adv. Hort. Sci., 35(1): 21­32. NASSARAWA S.S., ABDELSHAFY A.M., XU Y., LI L., LUO Z., 2020 ­ Effect of light‐emitting diodes (LEDs) on the quality of fruits and vegetables during postharvest period: a review. ­ Food Bioprocess Techn., 14: 388­ 414. PINTOS F.M., HASPERUÉ J.H., VICENTE A.R., RODONI L.M., 2020 ­ Role of white light intensity and photoperiod during retail in broccoli shelf‐life. ­ Postharvest Biol. Techn., 163: 111­121. POONIA A., PANDEY S., VASUNDHAR A., 2022 ­ Application of light emitting diodes (LEDs) for food preservation, post‐harvest losses and production of bioactive compounds: A review. ­ Food Prod., Processing Nutr., 4: 1­10. POTT D.M., VALLARINO J.G., OSORIO S., 2020 ­ Metabolite changes during postharvest storage: effects on fruit quality traits. ­ Metabolites, 10: 187. PRAJAPATI U., ASREY R., VARGHESE E., SHARMA R.R., 2021 a ­ Effects of calcium lactate on postharvest quality of bitter gourd fruit during cold storage. ­ Physiol. Mol. Biol. Plants, 27: 1811­1821. PRAJAPATI U., ASREY R., VARGHESE E., SINGH A.K., PAL SINGH M., 2021 b ­ Effects of postharvest ultraviolet‐C treatment on shelf‐life and quality of bitter gourd fruit during storage. ­ Food Packaging Shelf Life, 28: 100­ 665. PSA, 2022 ­ 2022 Selected statistics on agriculture and fisheries. ­ Philippine Statistics Authority. ROSARIO T., MACUSI E., 2009 ­ Morphological characterization and determination of the total alkaloid and saponin content of 15 accessions of bittergourd (Momordica charantia L.). ­ Philippine J. Crop Sc., 34: 21­ 32. SALAS F.M., ADVINCULA M.T., SALAS R.A., 2019 ­ Efficacy trial of innovative liquid nutrient formulations for kale (Brassica oleracea var. acephala L.) production under aggregate hydroponic system. ­ J. Nat. Studies, 18(1): 65­75. SALAS R.A., GODOY R.M.R., SALAS F.M., MENZIES N., HARPER S., ASIO V.B., 2020 ­ Yield and postharvest qualities of two genotypes of eggplant (Solanum melongena L.) applied with different levels of chicken dung. ­ Environ. Asia, 81­86. SALAS R.A., POLE V.N., SALAS F.M., QUEVEDO M.A., 2015 ­ Shelf‐life and free radical scavenging activity of bittergourd (Momordica charantia L.) coated with phytochemical extracts. ­ Acta Horticulturae, 1088: 247­ 250. SAXENA D., SABIKHI L., CHAKRABORTY S.K., SINGH D., 2012 ­ Process optimization for enzyme aided clarification of watermelon juice. ­ J. Food Sci. Techn., 51: 2490­2498. SURIATI L., MANGKU I.G.P., DATRINI L.K., HIDALGO H., RED J., 2022 ­ Effect of Aloe‐gel and bignay fruit proportions to acidity, total dissolved solids, and color of Aloe‐ bignay beverage. ­ Proceedings of the 1st Warmadewa International Conference on Science, Technology and Humanity. TAITI C., CAPARROTTA S., MANCUSO S., MASI E., 2017 ­ Morpho‐chemical and aroma investigations on autochthonous and highly‐prized sweet cherry varieties grown in Tuscany. ­ Adv. Hort. Sci., 31(2): 121­129. TESFAY S.Z., MAGWAZA L.S., 2017 ­ Evaluating the efficacy of moringa leaf extract, chitosan and carboxymethyl cellulose as edible coatings for enhancing quality and extending postharvest l ife of avocado (Persea americana Mill.) fruit. ­ Food Pack. Shelf Life, 11: 40­48. THILINI DEEPASHIKA PERERA W.P., NAVARATNE S., WICKRAMASINGHE I., 2022 ­Impact of spectral composition of light from light‐emitting diodes (LEDs) on postharvest quality of vegetables: A review. ­ Postharvest Biol. Techn., 191: 111­955. VALIDA A., RIVERA F.R., SALABAO A., BENITEZ M., SUDARIA E., ACEDO A., EKMAN J., 2018 ­ Bitter gourd (Momordica charantia) quality grading at two storage temperatures. ­ Acta Horticulturae, 1213: 293­296. VALYAIE A., AZIZI M., KASHI A., SATHASIVAM R., PARK S.U., SUGIYAMA A., MOTOBAYASHI T., FUJII Y., 2021 ­ Evaluation of growth, yield, and biochemical attributes of bitter gourd (Momordica charantia L.) cultivars under Karaj conditions in Iran. ­ Plants, 10: 1370. WILLS R., MCGLASSON B., GRAHAM D., JOYCE D., 1998 ­ Postharvest: an introduction to the physiology and handling of fruit, vegetables and ornamentals. ­ Oxford University Press, Oxford, UK, pp. 280. WITKOWSKA I., 2013 ­ Factors affecting the postharvest performance of fresh‐cut lettuce . ­ PhD Thesis, Wageningen University and Research, Wageningen, The Netherlands. YAHIA E., CARRILLO­LÓPEZ A., SAÑUDO A., 2019 ­ Physiological disorders and their control, pp. 499­527. ­ In: YAHIA E. (ed.) Postharvest technology of perishable horticultural commodities. ZHAN, L., HU, J., PANG, L., LI, Y., SHAO, J., 2013 ­ Effects of light exposure on chlorophyll, sugars and vitamin C content of fresh‐cut celery (Apium graveolens var. dulce) petioles. ­ Inter. J. Food Sci. Techn., 49: 347­353. Ponteras et al. ‐ Postharvest bittergourd as influenced by illumination colors 167 ZHOU F., ZUO J., XU D., GAO L., WANG Q., JIANG A., 2020 ­ Low intensity white light emitting diodes (LED) application to delay senescence and maintain quality of postharvest pakchoi (Brassica campestris L. ssp. chinensis (L.) Makino var. communis Tsen et Lee). ­ Scientia Horticulturae, 262: 109060. ZHU X., WANG Q., CAO J., JIANG W., 2008 ­ Effects of chitosan coating on postharvest quality of mango (Mangifera indica L. cv. Tainong) fruits. ­ J. Food Proc. Preser., 770: 32­84.