PAPER 260 Ital. J. Food Sci., vol. 27 - 2015 - Keywords: canned vegetables, extra-virgin olive oil, oxidation, preservation, soybean oil, sunflower oil - COMPARATIVE STUDY OF OXIDATION IN CANNED FOODS WITH A COMBINATION OF VEGETABLES AND COVERING OILS E. BRAVI*, A. MANGIONE, O. MARCONI and G. PERRETTI Department of Agricultural, Food and Environmental Science, University of Perugia, Via S. Costanzo n.c.n., 06126 Perugia, Italy * Corresponding author: Tel. +39 075 5857923, Fax +39 075 5857946, email: e_bravi@yahoo.it ABSTRACT The effects of sunflower (SFO), extra-virgin olive (EVO), and soybean oils (SBO), in combination with canned aubergins and dried tomatoes were studied during an accelerated shelf-life trial. Hy- drolytic and oxidative quality parameters was determined and a sensorial test was run. For both canned vegetables, the SBO showed greater resistance to the oxidation at the end of the shelf- life trial. The SBO in both vegetables yielded similar results for peroxide formation, whereas a re- duced formation of secondary oxidation products was observed in aubergins. The results high- lighted a higher oxidation stability of canned vegetables in SBO and EVO than those in SFO. The sensorial test underlined differences between the oils, in aubergins and dried tomatoes, after 30 days of accelerated storage (corresponding to the sell-by date). Flavour and texture were judged better for vegetables in SBO. Ital. J. Food Sci., vol. 27 - 2015 261 1. INTRODUCTION Canned foods are products packed and her- metically sealed in metal (tin, aluminum), glass, or polymer containers that are thermally treat- ed to destroy spoiling microorganisms and their enzymes with the aim to prolong the shelf-life. (LEISTNER, 1992). Moreover, the process of prepa- ration and preservation could increase the quality of vegetable products because of the presence of added oils as cover liquids (LEISTNER, 1992). In canned vegetables: i) the covering oil promotes an- aerobic conditions (i.e., less than 2% oxygen); ii) an adequate blanching treatment reduces num- bers of contaminating microorganisms, inacti- vates enzymes, modifies texture, preserves color, flavor, and nutritional value, and removes trapped air; and iii) pasteurization guarantees commer- cial sterility (REYES DE CORCUERA et al., 2004; BAIANO et al., 2005a). In the food industry, vir- gin and extra-virgin olive oil, olive oil, seed oils, or various oil blends, are used as covering oils to prepare preserved vegetables. The quality of canned vegetables in-oil depends on the complex interactions between traits of the vegetables and those of the covering oils. During storage, many bioactive molecules migrate from the vegetable to the oil and vice versa, in a dynamic equilibrium that depends on the characteristics (e.g., chem- ical composition, structure, size, and shape) of vegetables and oils as well as on the technolo- gy used for preparation and storage (LUCCHET- TI et al., 2011). Spices and aromatic herbs, gen- erally used as flavor enhancers in preparation of canned vegetables, also contribute to the quality of the canned product. They contain substanc- es with documented antimicrobial, antioxidant and anti-inflammatory activities (GAMBACORTA et al., 2007). The shelf-life of in-oil canned vegetables de- pends on the quality of the vegetable and the covering oil and its composition (BAIANO et al., 2005a). During processing and over the time, vegetables and oils undergo modifications be- cause of mechanical and thermal degradation and hydrolytic and oxidative degradation (af- fecting the quality of oil and preserved food) (DE GIORGI et al., 2000; BAIANO et al., 2005b). Some studies have examined the oxidative and hydrolytic reactions that occur in the covering oil, and on the effects of the use of different oils as a covering medium on the canned veg- etables preservation (LEISTNER, 1992; BAIANO et al., 2005a; BAIANO et al., 2005b; BAIANO et al., 2005c). The aim of the present paper was to compare the effects of the combination of different veg- etables and covering oils in canned foods. Sun- flower oil (SFO), extra-virgin olive (EVO) and soy- bean oil (SBO) in combination with canned au- bergins and dried tomatoes were studied. The quality of covering oils was studied to verify the effect of these combinations during storage. Hy- drolytic and oxidative quality parameters were measured together with sensory analysis. SFO was examined because of its wide use in the pro- duction of canned foods, EVO was examined be- cause of its sensorial and nutritional properties, and SBO was examined for its nutritional value, widespread use, and low cost. Moreover, the effects of aromatic herbs and spices (ingredients included in the recipes for canned vegetables) on oxidative degradation of the three oils were examined as a separate test on pure oils. The herbs and spices in the reci- pe were: i) garlic, rich in flavonoids and sulfur- containing compounds (LEELARUNGRAYUB et al., 2006); ii) chili pepper, containing allicin, carot- enoids, ascorbic acid, and phenolic compounds (SUHAJ, 2006); iii) oregano, containing various flavonoids (KYOJI et al. 2006); and iv) mint, rich in polyphenols and flavonoids (KANATT et al., 2007; PADMINI et al., 2008). 2. MATERIALS AND METHODS Both commercial in-oil canned aubergins and dried tomatoes were prepared according to tra- ditional recipes with three different vegetable oils (SFO, EVO, and SBO). The oil samples were provided by Vizzino “Orto Buono,” Minervino di Lecce, Italy. All canned products were produced on the same day and analysed, at time zero (T0) and 15 days after processing (T1). 2.1. Preparation of in-oil canned vegetables The canned vegetables used were aubergins in SFO (AUSFO), EVO (AUEVO), or SBO (AUS- BO), and dried tomatoes in SFO (DTSFO), EVO (DTEVO), or SBO (DTSBO). Traditional recipes in- cluded the addition of chili pepper (0.001 g kg-1 of total product), oregano (0.001 g kg-1), mint (0.001 g kg-1), and garlic (0.004 g kg-1) for canned auber- gins and mint (0.001 g kg-1) and garlic (0.004 g kg-1) for canned sun-dried tomatoes. A batch of 150 kg of 1 cm slices of peeled aubergins were previously treated with coarse salt (20% w/w), then drained and washed with water and centri- fuged. Then the slices of aubergins dehydrated were mixed with powdered herbs and spice (chi- li pepper, garlic, oregano, and mint) and a dose of 280g was put in transparent glass vessels, wrapped with metal caps. Vessels were then filled in the three considered oils (vegetables 65%, oil 33%, w/w) and hermetically sealed. A batch of 150 kg of dried tomatoes were blanched in boil- ing white vinegar for 30 seconds, then drained and dried, mixed with aromatic herbs (garlic and mint). Transparent glass vessels were filled with 280g of tomatoes and in the three considered oils (vegetables 65%, oil 33%, w/w), and hermetical- ly sealed. The canned samples were pasteurized at 90°C for 40 minutes, and then quickly cooled to room temperature. 262 Ital. J. Food Sci., vol. 27 - 2015 2.2. Aromatic herbs and spices added to oils A case study (separate test on pure oils with herbs and spices) was conducted to investigate the efficacy as antioxidant, and to verify the pro- tective effects of aromatic herbs and spices pre- sent as ingredients in the traditional recipes for considered canned foods. For this purpose SFO, EVO, and SBO, used in canned food prepara- tion, were prepared with the different aromat- ic herbs and spice used in the recipe: chili pep- per, garlic, oregano and mint (to investigate the effect of each single herb or spice); a mixture of mint and garlic (to simulate the dried tomatoes recipe); and a mixture of all the aromatic herbs and spice (to simulate the aubergins recipe). The spice and aromatic herb contents were chosen to simulate the same concentrations used in the recipes for canned vegetables in oils. The sam- ples to analyze were: i) SFO, EVO, or SBO, with added garlic (0.1 g/100mL of oil); ii) SFO, EVO, or SBO with added chili pepper (0.03 g/100mL); iii) SFO, EVO, or SBO with added oregano (0.03 g/100mL); iv) SFO, EVO, or SBO with added mint (0.03 g/100mL); v) SFO, EVO, or SBO with added mint and garlic (0.03 g/100mL and 0.1 g/100mL, respectively); and SFO, EVO, or SBO with all aromatic herbs and spice under consid- eration added. The samples were subjected to the same Ac- celerated Shelf-Life Test (ASLT) for canned veg- etables and the extent of the hydrolytic and ox- idative degradation of oils was determined by assessing peroxide numbers and p-anisidine values. 2.3. Accelerated Shelf-Life Test (ASLT) To evaluate the shelf-life of the canned vege- tables and of the pure oils with added herbs and spices, an accelerated shelf life test (ASLT), in which the storing of canned foods for 1 day at 55 °C corresponds to 18 days at room temperature (20°C), was performed (ROBERTSON, 1993; KIL- CAST, 2000; MAN, 2015). Accelerated aging was defined according to a common industrial method based on the Arrhenius equation, which defines the relationship between product shelf-life and the temperature (ROBERTSON, 1999; GIMÉNEZ et al., 2012; MARCONI et al., 2014;). The glass ves- sels with the vegetables canned in different cov- ering oils were kept in a laboratory oven (Thermo Fisher Scientific, Milan, Italy) at 55°C for 10, 20, 30, and 40 days, which corresponds to 6 (T1), 12 (T2), 18 (T3) and 24 (T4) months at room temper- ature, respectively. The vegetable oils were then subjected to chemical and sensorial analysis. 2.4. Chemical analyses The quality of the crude oils and the ongoing hydrolysis and oxidation of the covering oils were monitored by measurements of the acidity, ex- pressed as g of oleic acid per 100 g of oil; perox- ide values, expressed as milliequivalents (mEq) of active oxygen per kg of oil (E. U, 1348/2013), p-anisidine values (AOCS, 1998). The hydrolyt- ic and oxidative parameters were determined by conventional methods of analysis. After separa- tion from the vegetable matrices, the covering oil samples were filtered on anhydrous sodium sul- fate and analysed after different storage times. 2.5. Sensory evaluation Sensorial test was conducted to evaluate the palatability of the canned vegetables preserved in different oils at T0 and T3 (at the sell by date of canned food). Nine trained panelists (six wom- en and three men), 30–50 years, evaluated the canned vegetables using the quantitative de- scriptive analysis technique. The panelists were trained in 10 sessions, us- ing standards and similar food products, to iden- tify and determine descriptors relating to appear- ance, taste, and texture. The terms and the cor- responding definitions (Table 1) were available to the panelists during all sessions. The evalua- tion of the canned vegetables was performed over two days in two sessions. Canned vegetables were served at room temperature. Crackers were used as a carrier for tasting. Different canned vegeta- bles, in the different covering oils, were evalu- ated for sensory attributes, which included ap- pearance (color), flavor (rancid, salty, and bitter), and texture (hardness and chewiness). A 10-point Table 1 - Definition of physical and flavor descriptors used in the quantitative descriptive analysis. Descriptor Definition Physical Color Intensity of vegetable color. Hardness By steadily compressing the vegetable between the molars, the force required for compression. Chewiness The lenght of the time required to masticate the vegetable to a state of swallowing. Flavour Rancidness Unpleasant, stale smell or taste proper of oils and fats. Saltiness Taste of salt perceptible on the tip of the tongue and on the sides around it. Bitterness Harsh, disagreeably acrid taste. Ital. J. Food Sci., vol. 27 - 2015 263 scale (from 0 to 9) was used where color (0 = ex- tremely light to 9 = extremely dark); hardness (0 = extremely soft to 9 = extremely hard); chewiness (0 = none to 9 = extremely gummy); and rancidi- ty, saltiness, and bitterness (0 = none to 9 = ex- tremely strong) were assessed. 2.6. Statistical analysis All data were analysed using SigmaStat (version 11, Jandel Scientific, San Rafael, CA) software to perform the appropriate statistical tests. Com- parisons of the different vegetable and oil sam- ples were made using one-way repeated measures analysis of variance, and the results obtained were further analysed using the Holm-Sidak test. Each canned vegetable sample was produced in duplicate and all chemical analyses were per- formed in triplicate. Values were considered sig- nificantly different at p < 0.05. 3. RESULTS AND DISCUSSION 3.1. Oils The quality parameters (free acidity, peroxide values, p-anisidine values, and fatty acid compo- sition) of the three oils, employed as covering oils in the preparation of canned vegetables, are dis- cussed. The acidity values were lower than 0.3% in all samples (0.11, 0.28, and 0.15 g oleic acid/100g for SFO, EVO, and SBO, respectively), which con- firms low levels of hydrolytic activity in the oils comparable with cold pressed and virgin oils (CO- DEX-STAN 210-1999; EC, 1513/2001). The per- oxide values were low for all oils (4.22, 13.55, and 2.93 meqO 2 /kg, for SFO, EVO, and SBO, respec- tively), even if comparatively high in EVO (a value that was below the legal limits (EEC, 2568/91). The p-anisidine values in the three oils were low according to GUPTA (2005) and LIST et al. (1974), and the lowest value was observed for SBO (6.39, 6.42, and 1.95 for SFO, EVO, and SBO, respec- tively). 3.2. Preserved vegetables The free acidity values of the covering oils for canned aubergins and dried tomatoes during the ASLT are reported in Fig. 1. Free Fatty Ac- ids (FFA) are formed by chemical or enzymatic hydrolysis of triglycerides and may get promot- ed by the reaction of oil with moisture (natural- ly present in vegetables), FFAs content is an im- portant measure of alteration for oils. In all con- sidered sample the free acidity increased during the accelerated aging. Fig. 1 - Free acidity of covering oils in canned aubergins (a) and in canned dried tomatoes (b) as a function of stor- age. n = 6; bars in the figures represent standard de- viation values; EVO = extra-virgin olive oil. T0: 0 days; T1: 10 days; T2: 20 days; T3: 30 days; T4: 40 days 264 Ital. J. Food Sci., vol. 27 - 2015 For canned aubergins (Fig. 1a), the FFAs per- centage increased from 0.21 to 0.68% for SFO, from 0.35 to 0.60% for EVO, and from 0.30 to 0.46% for SBO. For canned dried tomatoes (Fig. 1b) and the three different covering oils used, the free acidity increased during the ASLT. The FFAs contents increased from 0.27 to 0.67% for SFO, from 0.43 to 0.92% for EVO, and from 0.28 to 0.58% for SBO. Despite contact with the moist vegetable matrix, the acidity values were satisfactory. Af- ter 30 days of ASLT (18 months of convention- al storage at room temperature), the changes in acidity for both aubergins and tomatoes were less than 1%. For aubergins, the acidity value for EVO was under the maximum limit for extra- virgin olive oil (EU, 61/2011), and for tomatoes, the value exceeded the maximum legal limit af- ter 30 days of accelerated aging, anyway after the sell-by date of the canned product. Fig. 2 shows the peroxide values and the p- anisidine numbers of the different covering oils for the canned aubergins (Fig. 2a) and dried to- matoes (Fig. 2b), respectively. The peroxide val- ue indicates the level of rancidity that normal- ly occurs in oils because of progressive unsat- urated fatty acid oxidation. For canned auber- gins (Fig. 2a), at T0, which corresponds to the fresh product, the peroxide values were unal- tered or, for SBO, slightly increased with re- spect to the pure oils used as covering medi- um. The peroxide values for the product at the beginning of the shelf-life trial was similar for the canned dried tomato covering oils, near- ly the same for SFO and EVO, and slightly in- creased for SBO as compared to the peroxide values of the pure oils (Fig. 2b). In all preserved vegetables, the peroxide values decreased after the beginning of the shelf-life trial while perox- ide compounds were progressively decomposed into secondary oxidation products (aldehydes and ketones and polymers) which corresponds in an increase of p-anisidine value. The p-ani- sidine value reveals the presence of secondary oxidation products. In canned aubergins, the peroxides were reduced to one-half the initial value at the end of ASLT (Fig. 2a); in canned dried tomatoes, the decrease in peroxides was more rapid and was about 1 mEq O 2 /kg after 40 days of accelerated aging (Fig. 2b). As shown in Fig. 2, the p-anisidine values of the oils used for covering the preserved vegeta- Fig. 2 - Peroxide number and p-anisidine value in canned aubergins (a) and in canned dried tomatoes (b), covered with sun- flower oil, extra-virgin oil, and soybean oil, as a function of storage. n = 6; bars in the figures represent standard deviation values. T0: 0 days; T1: 10 days; T2: 20 days; T3: 30 days; T4: 40 days Ital. J. Food Sci., vol. 27 - 2015 265 bles showed a progressive increase during the ASLT. For canned aubergins (Fig. 2a), p-anisidine values for EVO and SBO covering oils were sig- nificantly lower (p < 0.05) than that for SFO for the period of storage, and the decomposition of the hydroperoxides proceeded at a greater rate in SFO than in the EVO or SBO. As compared with the p-anisidine values found for EVO, the p-anisidine values of soybean oil were lower from two to four weeks of accelerated storage. SBO had the lowest oxidative rancidity dur- ing the ASLT. Comparing the results of the two types of canned vegetables, the p-anisidine val- ues of the covering oils for dried tomatoes were higher than those for aubergins during ASLT. However, as in canned aubergins, the p-anisi- dine numbers of tomatoes in SBO were signifi- cantly lower than those of the other oils consid- ered at the sell-by date (Fig. 2b). Since the data underlined the lowest content of hydroperoxides and the simultaneous lowest value of p-anisidine for aubergins and dried to- matoes in SBO and since the SBO showed the lowest value of free acidity, we may conclude that SBO has appreciable characteristics of stabili- ty to oxidation as covering oil in canned vegeta- bles. A high stability of SBO under the similar conditions of storage was underlined by WARN- ER et al. (1989) in a previous study. Dried tomatoes exhibited a higher index of secondary oxidation (p-anisidine value) than aubergins. At the sell-by date (18 months, 30 days of accelerated aging), the p-anisidine val- ue of canned dried tomatoes was 12.66 ± 0.02, 17.38 ± 0.10, and 17.53 ± 0.10 for SBO, EVO, and SFO respectively. Conversely, in aubergins, the highest p-anisidine value at the sell-by date was 10.80 ± 0.13 in SFO. Differences in oxida- tion of covering oils for aubergins and dried to- matoes could justify consideration of the addi- tive protective effects of antioxidant compounds present in aubergins (such as phenolic com- pounds, flavonoids, ascorbic acid, and vitamin A) and in dried tomatoes (lycopene, ascorbic acid, phenolic, flavonoids, and vitamin E) (HUNG and DUY, 2012), and the antioxidant effects of aro- matic herbs and spices added (chili pepper, gar- lic, oregano, and mint). Aubergin is one of the most active vegeta- bles in its free radical scavenging capacity be- cause of its phenolic constituents (JUNG et al., 2011; HUNG and DUY, 2012). Considering aro- matic herbs and spices, the antioxidant effects of the pungent component of chili pepper, cap- saicin, has been documented in previous stud- ies (REYES-ESCOGIDO et al., 2011). HENDERSON and HENDERSON (1992) observed that the oxi- dation of oleic acid at cooking temperatures was inhibited by the presence of capsaicin. In addi- tion, capsaicin is reported to inhibit lipid per- oxidation (SALIMATH et al., 1986; PULLA REDDY and LOKESH, 1992; ASAI et al., 1999; HENDER- SON et al., 1999; OKADA and OKAJIMA, 2001; KOGURE et al., 2002). Garlic has been reported to reduce free radical-induced oxidative damage in animal and human models. Extensive stud- ies performed on garlic extracts (Allium sativum L.) highlighted the presence of two main class- es of antioxidants: flavonoids and sulfur-con- taining compounds (LEELARUNGRAYUB et al., 2006). The four main garlic antioxidant com- pounds are alliin, allyl cysteine, allyl disulfide, and allicin (BENKEBLIA, 2005; EL SHENAWY et al., 2008). Oregano (Origanum majorana) is one of the aromatic herbs known to possess antiox- idant compounds such as rosmarinic acid, caf- feic acid, and various flavonoids. Oregano ex- tracts have shown a pronounced effect on sta- bilizing lipids against autoxidation (KYOJI et al. 2006). The effectiveness of mint, a common ar- omatic herb, as a natural antioxidant is wide- ly documented (KANATT et al., 2007; PADMINI et al., 2008; SAZHINA et al., 2011). For canned au- bergins, the antioxidant capacity arises from the typical antioxidant compounds of the vegetable and of garlic, mint, oregano and chili pepper; for preserved dried tomatoes, the antioxidant capac- ity arises from the vegetable and garlic and mint. The antioxidant capacity of aubergin is higher than that of dried tomato (WU et al., 2004). The aromatic herbs added to canned dried tomatoes were mint and garlic, and the additive effect of these two herbs may be lower than that of the canned aubergins and the herbs and spices used for it. Different results for the two canned foods may have been caused by their different anti- oxidant properties and the different added aro- matic herbs and spices. To confirm the above hypothesis, aromatic herbs and spices were added to the pure oils used as packing oils for the vegetables consid- ered. Each oil used for each vegetable had dif- ferent aromatic herbs and spices in the reci- pe (chili pepper, garlic, oregano, and mint), a mixture of mint and garlic, or a mixture of all aromatic herbs and spices together, and was analysed for peroxide numbers and p-anisi- dine values. The results are reported in Figs. 3, 4 and 5. The peroxide numbers and p-anisidine values of the three oils considered were influenced by the added aromatic herbs and spices. In particu- lar, during the ASLT, the oil samples with add- ed garlic, with added mint and garlic, and with all herbs and spices added presented lower val- ues of the oxidation parameters. In SFO, a high- er peroxide number was observed in the sample without spices and herbs, whereas chili pepper, oregano, and mint, showed an antagonistic ef- fect on peroxide formation. For p-anisidine, low- er values were observed in oil with added garlic and in oil with all herbs and spices added, where- as the oil with added mint and garlic had higher values; however, these values were lower than those found with other added herbs and spices. 266 Ital. J. Food Sci., vol. 27 - 2015 Fig. 3 - Peroxide number and p-anisidine value of extra-virgin olive oil (a), sunflower oil (b), and soybean oil (c), without herbs and spices and with different herbs and spices, as a function of storage. n = 6; bars in the figures represent standard deviation values. EVO = extra-virgin olive oil. T0: 0 days; T1: 10 days; T2: 20 days; T3: 30 days; T4: 40 days. A similar result was found for EVO where a low peroxide number was observed in oil samples with added garlic, and with all herbs and spic- es added. Samples with added mint and garlic had the same results as EVO with added orega- no. The lower p-anisidine value for EVO was ob- served with added garlic, added mint and garlic, and when all herbs and spices were added. For SBO, each of the aromatic herbs and spices in- fluenced the peroxide number and p-anisidine value. A higher protective effect was found for added garlic and for samples with all herbs and spices added. The oil with mint added had a p- anisidine value similar to the sample with add- Ital. J. Food Sci., vol. 27 - 2015 267 Fig. 4 - Peroxide number and p-anisidine value of sunflower oil, without herbs and spices and with different herbs and spic- es, as a function of storage. ed mint and garlic, which was lower than that for other herbs and spices. For SBO, the worst p-anisidine values were found in SBO with add- ed oregano (the oregano showed, in the case of SBO, an unusual pro-oxidant effect). The sensorial test underlined differences among the covering oils for each vegetable at T0 and at T3 (fresh product and product at its sell- by date). Table 2 shows the results for quantita- tive descriptive analysis for AUSFO compared to AUEVO and with AUSBO at T0 and at T3. At T0, AUEVO was significantly different (p < 0.05) from AUSFO and AUSBO with respect to its color and bitterness, which were judged to be higher than 268 Ital. J. Food Sci., vol. 27 - 2015 Fig. 5 - Peroxide number and p-anisidine value of soybean oil, without herbs and spices and with different herbs and spic- es, as a function of storage. those found for the other oils. These differenc- es could be explained by the characteristics of EVO. AUSBO was found to have lower rancid- ity when compared with the other samples. At the sell-by date, the quality of AUSBO differed from the other oils in its hardness, chewiness, and bitterness. AUSBO was judged slightly hard- er, less gummy, and less bitter than the other products. Table 3 shows the results for DTSFO as compared to DTEVO and DTSBO at T0 and at T3. At T0, DTEVO was judged to differ from DTSFO and DTSBO with respect to its bitter- ness, which was slightly higher than that of the other products. DTSBO was found to have lower Ital. J. Food Sci., vol. 27 - 2015 269 rancidity and saltiness than the other samples. At T3 the DTEVO was judged to differ from the other samples in its color and rancidness, and DTSBO was reported to be less gummy and less rancid than the other oil samples. 4. CONCLUSIONS The results obtained from this study underline the higher resistance to oxidation of vegetables canned in SBO and in EVO. A higher concentra- tion of secondary oxidation catabolites was ob- served in oils covering dried tomatoes than in oils covering aubergins. This might be related to the additive protective effects of antioxidant com- pounds found in the vegetables and the antiox- idant effects of added aromatic herbs and spic- es (HUNG and DUY, 2012). Data obtained from the case study, conduct to investigate the effica- cy as antioxidants of aromatic herbs and spice Table 2 - Sensory evaluation scores of AUSFO, AUEVO and AUSBO at T0 and T3. Sample ColorA HardnessB ChewinessC RancidnessD SaltinessD BitternessD AUSFO T0 6.70a 6.93a 5.96a 1.33a 4.46a 2.67a AUEVO T0 7.27b 7.10a 5.6a 1.13b 4.16a 3.13b AUSBO T0 6.63a 7.03a 5.30a 0.91c 4.13a 2.47a AUSFO T3 6.30a 5.39a 6.65a 1.22a 4.78a 3.96a AUEVO T3 6.57a 5.48a 6.21b 1.30a 4.48a 3.60a AUSBO T3 6.29a 6.43a 5.43a 1.45a 4.71a 2.58b n = 18; T0 = 0 months; T3 = 18 months. Pairs (AUSFO T0 compared with AUEVO T0 and with AUSBO T0; AUSFO T3 compared with AUEVO T3 and with AUSBO T3) with the different letters within the same column are significantly different (p < 0.05). AUSFO: aubergins in sunflower oil. AUEVO: aubergins in extra-virgin olive oil. AUSBO: aubergins in soybean oil. A = Color: 0 = extremely light to 9 = extremely dark. B = Hardness: 0 = extremely soft to 9 = extremely hard. C = Chewiness: 0 = none to 9 = extremely gummy D = Rancidness, saltiness, and bitterness: 0 = none to 9 = extremely strong present as ingredients in the traditional recipes for considered canned vegetables, confirm the higher antioxidant power found upon addition of all herbs and spices considered in the recipe, of an added mixture of mint and garlic, or of added garlic alone, as compared to the pure oils or the oils with other aromatic herbs and spices add- ed, and the minor effects on secondary oxidation of the oils with added mint and garlic. The sen- sorial investigation partially confirmed the an- alytical data at T0 with the finding of lower ran- cidity and, at the sell-by date, a better consist- ency and lower bitterness of aubergins in SBO. A lower rancidity at T0 and at T3 a better con- sistency and a lower rancidity were found for dried tomatoes in SBO. The lowest free acidity value, peroxides number, and p-anisidine value for aubergins and dried tomatoes in SBO, and the results of sensorial investigation underline the stability to oxidation and the validity of SBO as covering oil in canned vegetables production. Table 3 - Sensory evaluation scores of DTSFO, DTEVO and DTSBO at T0 and T3. Sample ColorA HardnessB ChewinessC RancidnessD SaltinessD BitternessE DTSFO T0 6.88a 6.73a 4.73a 1.01a 5.98a 2.66a DTEVO T0 6.67a 6.81a 4.83a 1.23a 6.32a 3.12b DTSBO T0 6.65a 6.26a 4.69a 0.86b 7.39b 2.53a DTSFO T3 6.81a 6.63a 4.93a 1.67a 5.57a 3.12a DTEVO T3 7.43b 6.43a 5.13a 2.13b 6.37b 3.16a DTSBO T3 7.06a 6.72a 4.13b 1.72c 5.45a 3.06a n = 9; T0 = 0 months; T3 = 18 months. Pairs (DTSFO T0 compared with DTEVO T0 and with DTSBO T0; DTSFO T3 compared with DTEVO T3 and with DTSBO T3) with the dif- ferent letters within the same column are significantly different (p < 0.05). DTSFO: dried tomatoes in sunflower oil. 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