Off-season mango production is predominant in tropical countries, mainly Thailand, Philippines, Indonesia, and some parts of peninsular India especially, Kanyakumari and areas of Tamil Nadu, due to the prevalent high temperature and relative humidity. Demand for off-season mango fruits is gaining prominence in the international markets of Asia and North America. Productivity of off- season fruits is negligible compared to the main-season mango under Indian conditions. The benefit of off-season mango production is higher profits to the farmer by avoiding a market glut. In off-season mango production, cv. Royal Special is the only variety bearing fruits during September- October (considered off-season) and in May-June, which is the main-season under South Indian conditions, owing to its multiple flushing and flowering pattern. Round fruits, yellowish-red in color, with a thick skin, abundant fiber, good Total Soluble Sugar (TSS) content (16.80Brix), with average fruit weight of 197.5g are the desirable traits in ‘Royal Special’ mango (Dinesh et al, 2012). Several authors have reported beneficial properties of the fruit such as lycopene, carotenoids, curcumins, phenolics, flavonoids and sugars, including their chemo- preventive role (Lakshminarayana et al, 1970; Kubo and Chemical constituents during the main and off-season in mango (Mangifera indica L.) cv. Royal Special S.R. Shivu Prasad, Y.T.N. Reddy, K.K. Upreti1 and V. Srilatha Division of Fruit Crops, ICAR-Indian Institute of Horticultural Research Hesaraghatta Lake Post, Bengaluru - 560 089, India E-mail: nreddy@iihr.ernet.in ABSTRACT Evaluation and quantification of fruit quality parameters like carbohydrates, phenolics, flavonoids, ascorbic acid, titrable acidity, Total Soluble Solids (TSS), carotenoids and lycopene content was done in fruits of mango cv. Royal Special, at ICAR-Indian Institute of Horticultural Research, Bengaluru, India, during the off-season (October, 2012) and main-season (June, 2013), respectively. ‘Royal Special’ is a typical off-season bearing cultivar, often characterized by multiple flushing and flowering under South Indian conditions. Major phytonutrients such as total sugars, reducing sugars, starch, total carotenoids, lycopene, total phenols, flavonoids, ascorbic acid, TSS, titrable acidity and average fruit yield per plant, were recorded during the off- and main- seasons. Results indicated that fruits from off-season were higher in the major chemical constituents studied compared to the main-season crop, except for fruit yield per plant. This may be attributed to poor competition for nutrients among the developing fruits which act as a sink, besides fluctuating environmental conditions during the off-season, compared to the main-season. Key words: Mango, cv. Royal Special, off-season, fruit yield, carbohydrates, pigments, total phenols, flavonoids Matsumoto, 1984; Lechaudel and Joas, 2007; Ojewole, 2005; Rodeiro et al, 2007). Most table-varieties exhibit an average TSS of 7.5-28.00Brix (Dinesh et al, 2012) under various climatic conditions. In addition to several other components, total carotenoids and ascorbic acid contribute are high in the mango pulp (Ross, 1999). Malundo et al (2001) reported that an ideal sugar:acid blend makes it favorable for flavonoid perception in ripe fruits. Pulp of Haden, Tommy Atkins and Uba varieties is a good source of total carotenoids, phenolics and ascorbic acid – components with antioxidant properties (Varakumar et al, 2011). Potential nutritional and health benefits of mango have gained great importance in fruit quality and marketing strategy of the fruit. As for fruit quality parameters, most of the earlier studies are restricted to the main-season, and information on off-season fruit quality parameters is scanty. Therefore, we aimed at a comparative study of off-season and main-season fruit quality parameters such as ascorbic acid content, total carotenoids, lycopene, total phenols, flavonoids, titrable acidity (TA), TSS, total sugars, reducing sugars, starch and fruit yield/plant in cv. Royal Special. The study was conducted at ICAR-Indian Institute of Horticultural Research, Bengaluru, India, on 21-year old, Short communication J. Hortl. Sci. Vol. 10(2):229-232, 2015 1Division of Plant Physiology & Biochemistry, ICAR-Indian Institute of Horticultural Research, Hesaraghatta Lake Post, Bengaluru-560089, India 230 uniformly-grown mango trees of cv. Royal Special, planted at 10m × 10m spacing having average canopy diameter of 8.0m. The experimental farm is located at 914.4m above mean sea level, with average temperatures ranging from 13.3 -32.40C during the year. The soil is sandy loam with available soil-nutrients N:250 kg/ha, P:30 kg/ha, K:300 kg/ ha, at pH 7.2, average silt 9% and clay 21.5%. The trees were raised under rainfed conditions. Six trees were selected randomly for sampling fruits. Samples of five mature fruits from each tree were drawn during early October, 2012 and late June, 2013. These were ripened at room temperature in both the seasons. During the fruit ripening, the average maximum and minimum temperature was 27.8/ 19.4oC and 30.1/20.8oC and ripening duration 5 and 8 days in October and June, respectively. Appearance of desired skin colour in the fruit peel, and olfactory perception of fruit aroma, were employed as indices of fruit ripening for laboratory analysis. Ripe fruits were then completely peeled- off, pooled, sliced, the kernel removed, weighed and samples subjected to further analysis for fruit pulp traits. TSS was estimated using a hand-held ERMA refractrometer, while TA was estimated as per Association of Official Analytical Chemists (AOAC) method, using phenolphthalein as an indicator. Total sugars in fresh samples were estimated following Hansel and Moller (1975). Reducing sugar content was determined by Somagyi (1952) method, and amount of reducing sugars calculated using a glucose standard. Non-reducing sugars were estimated by subtracting reducing sugars from the total sugar content. Starch content in fresh samples was determined using anthrone reagent, as per Hedge and Hofreiter (1962). For determining the content of total phenols and flavonoids, 1.0g fresh pulp was finely ground with 5.0ml 80% ethanol, centrifuged at 10000rpm for 10 min, supernatant collected and volume readjusted to an initial volume with 80% ethanol. Total phenols were estimated spectrophotometrically using Folin-Ciocalteu reagent (Bray and Thorpe, 1954) with gallic acid as the standard. The values were expressed as mg/ 100g fresh weight. Total flavonoid content was estimated using catechin as the standard, and the values were expressed as mg/100g fresh weight (Zhishen et al, 1999). Total carotenoids and lycopene content was estimated spectrophotometrically (Jensen, 1978; Ranganna, 1976). Molar extinction coefficient of 2500M-1 cm-1 at 450nm for total carotenoids, and 1.72x105 M-1 cm-1 at 503nm for lycopene was used for calculating their respective content. Ascorbic acid was estimated by extracting the fruit pulp in 5% metaphosphoric acid, and titrated with 0.05% aqueous 2,6-dichlorophenol-indophenol as per Harris and Olliver (1942). Data were statistically analyzed using ANOVA, and significance (p>0.01) was determined for comparing treatments. Total sugar content increased up to 50% during the off-season, at 132.95 mg/g in October, 2012, and 81.98 mg/ g in June, 2013. Significant variation was observed in the content of reducing sugars during off-season (63.09mg/g), while, during the main-season, 26.45mg/g was recorded (Table 1). Analogous to total and reducing sugars, the non- reducing sugars, the starch and TSS were found to be significant. Maximum content recorded was 69.89mg/g, 28.3mg/g and 210Brix, respectively, while minimum content recorded was 55.53mg/g, 17.2mg/g and 14 0Brix, respectively, during off-and on-seasons, respectively. Differences among carbohydrate and starch content can be attributed to differences in competing growth-aspects in the developing /ripening fruits. Increase in carbohydrate content can be correlated with increase in TSS in the fruit, noticed in the present study. Fruit development during September-October was perhaps facilitated optimally due to less fruit-load on the trees. These trees had been affected by the previous year’s crop-load. In simple terms, more the crop-load, higher the competition among developing fruits, and vice-versa. On the contrary, Burdon et al (2007) reported that carbohydrate status in avacado fruit was the same, irrespective of the season, under New Zealand conditions. In our studies earlier, non-reducing sugars were monitored at various stages in mango (Reddy et al, 2014). There is an added complication in fruit crops, especially in mango, in interpreting carbohydrate status of the fruit, due to asynchronous flowering. Titrable acidity (TA) had no determining role during either the main or the off-season. However, higher titrable acidity was recorded (0.32%) during off-season, and Table 1. Carbohydrates, TSS and ascorbic acid content in mango fruit Season Total sugars Reducing Non-reducing Starch TSS Ascorbic acid Titrable (mg/g) sugars (mg/g) sugar (mg/g) (mg/g) (oBrix) (mg/100g) acidity (%) Off-season 132.95±0.577 63.09±0.578 69.89±0.057 28.3±0.173 21±1.173 0.87±0.011 0.32±0.057 Main-season 81.98±0.562 26.45±0.259 55.53±0.303 17.2±0.577 14±1.154 0.67±0.011 0.25±0.056 (p significant >0.01, n=3) Shivu Prasad et al J. Hortl. Sci. Vol. 10(2):229-232, 2015 231 minimum TA (0.25%) was recorded in the main-season crop. Ascorbic acid content was 0.87mg/100g in off-season, and 0.67mg/100g in the on-season. Ascorbic acid content was 20% higher in off-season fruits. Higher content of phenolics and flavonoids was recorded during off-season (Table 2). The difference seen in flavonoid content between seasons can be directly correlated with sugar:acid blend. In support of our findings, a study by Malundo et al (2001) states that sugars and acids enhance human perception of specific flavor-notes in mango, including the aromatics. On the other hand, lower TSS:acid ratio is directly related to higher sourness (Lechaudel and Joas, 2007). Total carotenoid and lycopene content increased in off season fruits compared to the on-season ones, at a maximum of 4.47mg/100g and 1.01mg/100g, respectively while, minimal content recorded was 2.33mg/100g and 0.45mg/100g during the off- and on- season, respectively. These results were found to be significant (Table 3) increase in content of carotenoids and lycopene during the off-season can be directly correlated with fluctuating environment (stress), viz., temperature, light intensity, leaf photosynthetic capacity and rainfall, along with poor competition for nutrition demand in a growing fruit on the tree. Also, lower day temperatures were often seen to be associated with higher pigmentation in apple (Solovchenko et al, 2006). We too observed this in our study. Average fruit yield per plant reduced considerably during the off-season. Maximum fruit yield (40kg/plant) and minimum fruit yield (5kg/plant) was recorded in the on- and off-season, respectively, and these differences were significant. The present study revealed that differences in crop yield during the on- and off- years influenced biochemical factors in the fruit, especially carbohydrates, along with others like phenolics, flavonoids and carotenoids. Prior to this study, none of the research works on mango have shown clear-cut accumulation pattern and development of fruit quality parameters during main and off season grown mango fruits especially, in cv. Royal Special, which is erratic in flowering. From this study, it can be inferred that fruits grown in the off-season are richer in phytonutrients than those grown during the main-season crop. It is worthwhile to promote off-season production in mango cv. Royal Special. Table 2. Total flavonoids and phenols in mango fruit Season Phenols Flavonoids (mg/100g) (mg/100g) Off-season 0.817±0.009 0.481±0.047 Main-season 0.653±0.003 0.123±0.013 (p significant >0.01, n=3) Table 3. Carotenoids, lycopene content and average fruit yield in mango Season Carotenoids Lycopene Average fruit (mg/100g) (mg/100g) yield (kg/plant) Off-season 4.47±0.288 1.01±0.144 5.0±2.603 Main-season 2.33±0.191 0.45±0.025 40.0±5.773 (p significant >0.01, n=3) Fig. 2. Ripe fruits of mango cv. Royal Special Fig. 1. ‘Royal Special’ mango tree in different stages of growth Chemical constituents in mango during the main and off-season J. Hortl. Sci. Vol. 10(2):229-232, 2015 232 ACKNOWLEDGEMENT The authors are thankful to Director, ICAR-IIHR, for providing facilities and grateful to NAIP, ICAR New Delhi, India, for financial support. Thanks go out to National Coordinator-4 for providing encouragement in the course of the study. Active support of H.L. Jayaram, Technical Officer, T.N. Nagaraj, Field Technician, H.S. Naveen, Skilled Assistant and J. Varun, NAIP Project is gratefully acknowledged. REFERENCES AOAC. 1990. Official Methods of Analysis. Association of Official Analytical Chemists, Washington D.C., USA Bray, H.G. and Thorpe, W.V. 1954. Analysis of phenolic compounds of interest in metabolism. Methods Biochem. Anal., 52:1-27 Burdon, J., Lallu, N., Haynes, G., Pidakala P., Willcocks, P., Billing, D., McDermott, K., Voyle, D., and Boldingh, H. 2007. Carbohydrate status of late-season ‘Hass’ avocado fruit. New Zealand Avocado Growers’ Association Ann. Res. Rep., 7:97-102 Dinesh, M.R., Vasugi, C. and Reddy, Y.T.N. 2012. Mango catalogue. IC NO; 391846, pp. 282 Hansel, J. and Moller, I. 1975. Percolation of starch and soluble carbohydrates from plant tissue for quantitative determination with anthrone. Anal. Biochem., 68:87-94 Harris, L.J. and Olliver, M. 1942. Vitamin methods: The reliability of the method for estimating Vitamin C by titration against 2:6-dichlorophenolindophenol. 1. Control tests with plant tissues. Biochem. J., 36:155- 182 Hedge, J.E. and Hofreiter, B.T. 1962. In: Methods in Carbohydrate Chemistry, Vol. 17, Whistler, R.L. and Be Miller, J.N. (Eds), Academic Press, New York, USA Jensen, A. 1978. Chlorophylls and carotenoids. In: Hellebust, A. and Crargie, J. (Eds), Handbook of Phytological Methods, Cambridge University Press, London, pp. 59-70 Kubo, I. and Matsumoto, A. 1984. Molluscicides from olive, Olea europea, and their efficient isolation by counter- current chromatogrphies. J. Agri. Food Chem., 32:687-688 Lakshminarayana, S., Subhadra, N.V. and Subramanyam, H. 1970. Some aspects of developmental physiology of mango fruit. J. Hortl. Sci. Biotech., 45:133-142 Lechaudel, M. and Joas, J. 2007. An overview of pre-harvest factors influencing mango fruit growth, quality and post-harvest behaviour. Brazilian J. Pl. Physiol., 19:287-298 Malundo, T.M.M., Shewfelt, R.L., Ware G.O. and Baldwin, E.A. 2001. Sugars and acids influence flavour properties of mango (Mangifera indica). J. Amer. Soc. Hortl. Sci., 126:115-121 Ojewole J.A. 2005. Anti-inflammatory, analgesic and hypoglycemic effects of Mangifera indica Linn. (Anacardiaceae) stem-bark aqueous extract. Methods Find Expt’l. Clin. Pharmacol., 27:547- 54 Ranganna, S. 1976. Manual of analysis of fruits and vegetable products, Tata McGraw Hill publishers, New Delhi, pp. 634 Reddy, Y.T.N., Shivu Prasad, S.R. and Upreti, K.K. 2013. Effect of Paclobutrazol on fruit quality attributes in mango (Mangifera indica L.) cv. Totapuri. J. Hortl. Sci., 8:236-239 Rodeiro, I., Donato, M.T., Jimnenez, N., Garrido, G., Delgado, R. and Gomez-Lechon, M.J. 2007. Effects of Mangifera indica L. aqueous extract (Vimang) on primary culture of rat hepatocytes. Food Chem. Toxicol., 45:2506-2512 Ross, I.A. 1999. Medicinal plants of the world. Vol.1. Human Press, New Jersey, USA, pp. 199-200 Solovchenko, A.E., Avertcheva O.V. and Merzlyak, M.N. ý2006. Elevated sunlight promotes ripening-associated pigment changes in apple fruit. Postharvest Biol. Technol., 40:183-189 Somagyi, M. 1952. Notes on sugar determination. J. Biol. Chem., 195:19-23 Varakumar, S., Sudheer Kumar, Y. and Reddy, O.V.S. 2011. Carotenoid composition of mango (Mangifera indica L.) wine and its antioxidant activity. J. Food Biochem., 35:1538-1547 Zhishen, J., Mengcheng, T. and Jianming, W. 1999. The determination of flavonoid content in mulberry and their scavenging effects on superoxide radicals. Food Chem., 64:555-559 (MS Received 20 January 2015, Revised 27 August 2015, Accepted 08 September 2015) Shivu Prasad et al J. Hortl. Sci. Vol. 10(2):229-232, 2015