Charanjit Kaur

Antioxidants in tomato (Lycopersium esculentum) as a function of genotype

Consumption of tomato products has been associated with decreased risk of some cancer types. Epidemiological findings confirm the observed health effects due to the presence of varied antioxidants in tomato. The bio-antioxidant content and antioxidant activity of 12 tomato genotypes was therefore studied. Significant differences were found between lycopene, ascorbic acid and phenolic contents among various genotypes. Lycopene and ascorbic acid contents showed 1-4 fold and 1-2 fold variation on both fresh and dry weight basis, respectively. Antioxidant activity was found to vary significantly among genotypes. In both free radical quenching assay and FRAP assay, significant activity was found. Activity was higher in the hexane fraction containing lycopene than the methanol fraction containing phenolics. Tomato peels, in addition to lycopene, contain significantly high amounts of ascorbic acid and phenols. Cherry tomatoes, particularly variety 818 cherry, with the highest contents of antioxidants (lycopene, ascorbic acid and phenols) and highest antioxidant activity represents a valuable genotype not only for improving the status of dietary antioxidants in our diet but also for increasing nutritional value through germplasm enhancement programmes. The cherry varieties also merit considerable attention for processing because of their high total soluble solids and titrable acidity.

Variations in phenolics and antioxidants in Indian onions (Allium cepa L.): genotype selection for breeding.

Purpose – The purpose of this paper is to provide a comprehensive evaluation of 34 onion genotypes for their antioxidant activity (AOX) content of phenolics, quercetin and pungency to enable selection of the best genotype for later experiments of variety breeding or to be used as a vector in the improvement of well‐established traditional genotype.Design/methodology/approach – A comprehensive screening of 34 onion (red, pink and white) genotypes is carried out in order to determine the variation in phenolics, quercetin and total AOX as potential for breeding for their enhanced levels.Findings – The AOX in red genotype with highest levels of phenolics is roughly three times higher than commercial white genotype. Pungency levels range from 3.12 to 10.48  μmoles pyruvic acid/g. Mean phenolic and quercetin content ranges from 60.1 to 1094.8 mg gallic acid equivalents/kg and 22.0 to 890.5 mg/kg quercetin, respectively. AOX in red genotype (expressed as μmoles trolox/g) ranges from 1.97 to 5.45 and 3.60 to 6.61...

Lycopene content, antioxidant capacity and colour attributes of selected watermelon (Citrullus lanatus (Thunb.) Mansfeld) cultivars grown in India

The present investigation reports variability in lycopene, ascorbic acid, total phenolics, antioxidant capacity and colour attributes of 12 watermelon cultivars grown in India. Antioxidant capacity was evaluated using four in vitro assays, namely ferric reducing antioxidant power, cupric reducing antioxidant capacity, Trolox equivalent antioxidant capacity and 2,2-diphenyl-1-picryl hydrazyl. Among watermelon cultivars, significant differences (p < 0.05) were found with respect to lycopene content and antioxidant capacity. Lycopene content ranged from 03.46 to 8.00 mg/100 g fresh weight. Colour of watermelon flesh was described by an optimized colour index (CI). Cultivars ‘PWM25-4’, ‘Arun’, ‘Kiran’ and ‘Kareena’ were found to be the most promising ones with highest lycopene content, antioxidant capacity and CI. Results indicate that watermelon is a good source of dietary lycopene and there exists significant variation that can be exploited to produce high-quality cultivars.

Capsaicinoids, Tocopherol, and Sterols Content in Chili (Capsicum sp.) by Gas Chromatographic-Mass Spectrometric Determination

A gas chromatography-mass spectrometry method was developed for the quantitative determination of capsaicinoids, vitamin E, and phytosterols in chili peppers using a simple extraction technique for rapid screening. These components were extracted with acetonitrile and were injected into gas chromatography attached with mass spectrometry. The mean recovery values for triplicate analysis were between 90.6–99.7%. Besides major capsaicinoids (capsaicin, dihydrocapsaicin, nordihydrocapsaicin), four more minor capsaicinoids (nonivamide, nornordihydrocapsaicin, homodihydrocapsaicin I and II) were detected in chili samples. α-Tocopherol was also detected in the same run along with three phytosterols (campesterol, γ-sitosterol, and stigmasterol). Variations were observed across the chili sample in all of the constituents except a few minor capsaicinoids. The method was suitable for simultaneous estimation of capsaicinoids, vitamin E, and phytosterols in a single run from any types of pepper. Thus, the method is effective for rapid screening of peppers for its nutraceutical composition using single solvent extraction.

Improvement of antioxidant and defense properties of Tomato (var. Pusa Rohini) by application of bioaugmented compost.

Nutrient management practices play a significant role in improving the nutritional quality of tomato. The present study deals with the evaluation of compost prepared using Effective Microorganisms (EM), on antioxidant and defense enzyme activities of Tomato (Lycopersicon esculentum). A field experiment with five treatments (control, chemical fertilizer and EM compost alone and in combination) was conducted in randomized block design. An increment of 31.83% in tomato yield was recorded with the combined use of EM compost and half recommended dose of chemical fertilizers (N50P30K25 + EM compost at the rate of 5 t ha−1). Similarly, fruit quality was improved in terms of lycopene content (35.52%), antioxidant activity (24–63%) and defense enzymes activity (11–54%), in tomatoes in this treatment as compared to the application of recommended dose of fertilizers. Soil microbiological parameters also exhibited an increase of 7–31% in the enzyme activities in this treatment. Significant correlation among fruit quality parameters with soil microbiological activities reveals the positive impact of EM compost which may be adopted as an eco-friendly strategy for production of high quality edible products.

Effect of chitosan and alginate based coatings enriched with pomegranate peel extract to extend the postharvest quality of guava (Psidium guajava L.)

The influence of chitosan (1% w/v) and alginate (2% w/v) coatings in combination with pomegranate peel extract (PPE; 1% w/v) on quality of guavas (cv Allahabad safeda) were studied. Restricted changes were recorded in respiration rate, ripening index, and instrumental colour values in case of the coated samples as compared to the control for 20days at 10°C. Samples coated with chitosan enriched with PPE (CHE) proved to be the most effective treatment in maintaining the overall fruit quality. Ascorbic acid, total phenolics, total flavonoids contents and antioxidant activity were recorded with restricted losses of 29%, 8%, 12%, 12% (DPPH) and 9% (FRAP), respectively for CHE samples at the end of storage. A higher degree of correlation (r>0.918) was established between various phytochemicals and AOA. PPE enriched coatings was proved efficient in maintaining the quality of guavas during 20days of low temperature storage.

Antioxidant Activity and Total Phenolic Content of Kale Genotypes Grown in Kashmir Valley

Green leafy vegetable extracts of six genotypes of kale (Brassica oleracea acephala) were evaluated for ascorbic acid, carotenoids, total phenolics and antioxidant activity. Ascorbic acid ranged from 142 mg per 100 g in Wappal Hakh to 164 mg per 100 g fr wt in Knol khol. Wild genotypes Wappal and Pumb, had significantly high phenolic content (285 and 227 mg per 100 g fr wt) and possessed highest antioxidant activities (840 and 780 µmol FRAP per g fr wt) than cultivated genotypes. A positive and strong correlation (R2 = 0.807) between total phenolic content and antioxidant activity suggests that kale has enormous potential to enhance the antioxidant potential of our daily food supply. Wild genotypes, Wappal and Pumb can be incorporated into the breeding programmes in order to increase the antioxidant potential of cultivated varieties.

Nutraceutical composition of Zizyphus mauritiana Lamk (Indian ber): effect of enzyme-assisted processing

Zizyphus (Indian ber) is an excellent source of several phenolic compounds. The effect of two cell wall degrading enzymes, namely pectinase and viscozyme, on the nutraceutical composition of Zizyphus juice was investigated in the present study. Enzyme assisted processing significantly (P < 0.05) improved the juice yield, total soluble solids, total phenolics and total antioxidant activity (AOX). There was significant increase in recovery of antioxidants, to the tune of 70.51%, 66%, and 45% respectively in ascorbic acid, total phenolics and total flavonoids through viscozyme. The in-vitro total AOX of juice extracted via enzyme-assisted processing was 20.9 and 15.59 μmol Trolox/ml in ferric-reducing antioxidant power and cupric-reducing antioxidant capacity assays, respectively. There was 41% increase in AOX of juice extracted with enzyme over straight pressed juice. Results indicate that enzyme-assisted processing can significantly improve the functional properties of the Zizyphus juice.

Antioxidant Composition of Red and Orange Cultivars of Tomatoes (Solanum lycopersicon L): A Comparative Evaluation

Fourteen commercial cultivars of tomato were analyzed for their antioxidant composition. There was significant difference (p<0.05) in lycopene and phenolic contents between red and yellow cultivars. Red cultivars had higher lycopene content (2.735 to 6.552 mg 100g−1) than yellow cultivars (0.769 to 1.238 mg 100g−1). Mean total polyphenolic content and total antioxidant activity in red cultivars was also higher than those in yellow cultivars. Overall cherry tomatoes had highest phenolic content and appeared to be a promising cultivar in terms of their health promoting effects. The results highlight an existing unexploited variability in yellow tomato to improve their antioxidant properties.

Effect of Extrusion Processing on Phenolics, Flavonoids and Antioxidant Activity of Millets

The study was aimed to evaluate the effect of different extrusion treatments on total phenolic content, total flavonoids and antioxidant activity of finger millet and sorghum. The flours were subjected to eight different extrusion treatments at varying feed moisture, die head temperature and screw speed. Statistical analysis revealed that the total phenolic content (TPC), total flavonoid content (TFC) and antioxidant activity (FRAP, DPPH, TEAC) of extruded finger millet and sorghum flours was reduced significantly (p < 0.05) over their native counterparts. However, extrusion at high feed moisture, low temp and high screw speed (HM/LT/HS) retained considerable percentage of bioactives. Maximum retention of TPC, TFC and FRAP was observed as: 54%, 78% and 57% in finger millet respectively and 87%, 89% and 86% in sorghum, respectively. High retention of bioactives in extruded millet flours demonstrated their enormous potential for the development of phenolic and antioxidant rich ready-to-eat snacks.