Dalbir Singh Sogi

Effect of extraction conditions on lycopene extractions from tomato processing waste skin using response surface methodology.

Skin, rich in lycopene, is an important component of waste originating from tomato paste manufacturing plants. A central composite design with five independent variables, namely solvent/meal ratio (20:1, 30:1, 40:1, 50:1, and 60:1v/w); number of extractions (1, 2, 3, 4 and 5); temperature (20, 30, 40, 50 and 60°C); particle size (0.05, 0.15, 0.25, 0.35 and 0.43mm); extraction time (4, 8, 12, 16 and 20min) was used to study their effects on lycopene extraction. The experimental values of lycopene ranged between 0.639 and 1.98mg/100g. The second order model obtained for extracted lycopene revealed a coefficient of determination (R(2)) of 0.99 and a standard error of 0.03. Maximum lycopene (1.98mg/100g) was extracted when the solvent/meal ratio, number of extractions, temperature, particle size and extraction time were 30:1v/w, 4, 50°C, 0.15mm and 8min, respectively.

Total phenolics, antioxidant activity, and functional properties of ‘Tommy Atkins’ mango peel and kernel as affected by drying methods

Mango processing produces significant amount of waste (peels and kernels) that can be utilized for the production of value-added ingredients for various food applications. Mango peel and kernel were dried using different techniques, such as freeze drying, hot air, vacuum and infrared. Freeze dried mango waste had higher antioxidant properties than those from other techniques. The ORAC values of peel and kernel varied from 418-776 and 1547-1819 μmol TE/g db. The solubility of freeze dried peel and kernel powder was the highest. The water and oil absorption index of mango waste powders ranged between 1.83-6.05 and 1.66-3.10, respectively. Freeze dried powders had the lowest bulk density values among different techniques tried. The cabinet dried waste powders can be potentially used in food products to enhance their nutritional and antioxidant properties.

Total phenolics, antioxidant properties and quality of fresh-cut onions (Allium cepa L.) treated with mild-heat

This study investigated the effect of mild-heat on fresh-cut onion slices by treating in hot water (50, 60, 70°C) for 1 min. Total phenolics (TP), antioxidant properties, colour, and weight loss of slices were evaluated during 4°C storage at 7-day intervals (21 days total). The 60°C heat treatment resulted in a significant increase in TP, from 44.92 to 52.32 mg GAE/100g. Except for 50 and 70°C treatments, TP in control and 60°C treated fresh-cut onions decreased during storage. The antioxidant properties of fresh-cut onions were 1.31, 0.99, and 62.49 μM TE/g using ABTS, DPPH, and ORAC assays, respectively. The mild-heat treatments did not affect ABTS and DPPH antioxidant activities and the colour of fresh-cut onions. The storage time had mixed effect on the antioxidant properties (ABTS decreased; DPPH and ORAC remained fairly stable). The 50°C samples exhibited the lowest weight loss during 21-day storage.

Physicochemical, morphological and pasting properties of acid treated starches from different botanical sources

Effect of acid modification on physico-chemical, morphological and pasting properties of banana, sweet potato, lotus stem and wheat starches were studied. Results revealed that swelling power, solubility and water binding capacity of all starches decreased by acid modification. By acid modification starch granules from different varieties tended to appear fused and less smooth than the native starch granules. The pasting properties of native starches of all different varieties have significantly decreased following acid modification. Acid modified starches showed higher syneresis as compared to native starches.

Fractionation and electrophoresis of tomato waste seed proteins

Abstract Proteins of deoiled meal and alkali-extracted concentrate of tomato seeds were classified by successive extractions with sodium chloride (0.5 M), aqueous ethanol (70%) and acetic acid (0.05 M) into albumin, globulin, gliadin and glutenin. The globulin was the major protein in both meal and alkali-extracted concentrate. Native and sodium dodecylsulphate polyacrylamide gel electrophoresis of various fractions of seed meal and alkali extracted concentrate revealed that the proteins were made up of sub-units of lower molecular weights. It also indicated that different solvents extracted proteins having different molecular weights.

Thermal Degradation Kinetics of Pigments and Visual Color in Watermelon Juice

Thermal degradation of total carotenoids, lycopene and visual colour of watermelon juice was studied at 50–90°C up to 5 h. Total carotenoids content in fresh watermelon juice was reduced from 4.568 to 0.929 mg/100 g, lycopene from 4.403 to 0.82 mg/100 g and Hunter ‘a × b’ value from 251.66 to 89.59 when heated at 90°C for 5 h. First order model explained the degradation behaviour of total carotenoids, lycopene and Hunter ‘a × b’ value evident from correlation coefficient (R2) higher than 0.93. The dependence of degradation rate constant of total carotenoids, lycopene and Hunter ‘a × b’ value on temperature was adequately explained by Arrhenius equation. The activation energies for total carotenoids, lycopene and Hunter ‘a × b’ value were 24.19, 26.46, and 55.47 kJ/mol, respectively. Total carotenoids and lycopene were correlated with Hunter ‘a × b’ value with R2 > 0.99 indicating that visual colour may be used to predict lycopene and total carotenoids contents in watermelon juice.

Characterisation and functional properties of watermelon (Citrullus lanatus) seed proteins

BACKGROUND People in developing countries depend largely on non-conventional protein sources to augment the availability of proteins in their diets. Watermelon seed meal is reported to contain an adequate amount of nutritional proteins that could be extracted for use as nutritional ingredients in food products. RESULTS Osborne classification showed that globulin was the major protein (≥500 g kg (-1)) present in watermelon seed meal, followed by albumin and glutelin. Sodium dodecyl sulfate polyacrylamide gel electrophoresis indicated that the polypeptides had low molecular weights ranging from 35 to 47 kDa. Isoelectric focusing revealed that the isoelectric point of most proteins was in the acidic range 4-6. These proteins are rich in aspartic acid, glutamic acid and serine. An increase in pH (5-9) significantly (P < 0.05) decreased the denaturation enthalpy of these proteins. Among functional properties, albumin exhibited a much higher dispersibility index (810.3-869.6 g kg(-1)) than globulin (227.8-245.4 g kg(-1)), glutelin (182.1-187.7 g kg(-1)) and prolamin (162.3-177.7 g kg(-1)). Digestibility was in the ranges 760.6-910.0 and 765.5-888.5 g kg(-1) for Mateera and Sugar Baby watermelon protein fractions respectively, while surface hydrophobicity ranged from 126.4 to 173.2 and from 125.8 to 169.3 respectively. The foaming and emulsifying properties of albumin were better than those of the other proteins studied. CONCLUSION The good nutritional and functional properties of watermelon seed meal proteins suggest their potential use in food formulations.

Sorption Isotherms and Drying Characteristics of Tomato Peel Isolated from Tomato Pomace

Tomato peel was separated from pomace by sedimentation and dried in cabinet and fluidized-bed dryer at 50–70°C using 4–12 kg/m2tray load. The drying of tomato peel took place under the falling rate period and the drying behavior was well described by Pages model with coefficient of determination greater than 0.99 and standard error of 0.003–0.016. A fluidized-bed dryer was much more efficient than a cabinet dryer to dry tomato peel. The moisture adsorption isotherms of tomato peel were obtained by equilibrating above saturated salt solutions of known a w (0.113–0.92) at 20–60°C. The data were analyzed using fifteen sorption models based on coefficient of determination, standard error, and residual plots. Modified Henderson was the best model for tomato peel with coefficient of determination >0.99, standard error <0.210, and a scattered residual plot. The net isostearic heat of sorption, estimated using the Clausius-Clapeyron equation, was 0.74–23.23 kJ/mol at 2.0–2.5% moisture content (dry basis).

Extraction and Characterization of Pectin from Apple (Malus Pumila. Cv Amri) Peel Waste

Abstract Apple peel, the major waste in preserves manufacturing, contained 1.21% pectin. Peel waste could be stabilized with 600 ppm sulphur dioxide and 1% citric acid. Pectin extraction was better in citric acid than hydrochloric acid. The pectin powder was prepared by triple extraction with citric acid solution (1%) clarification through sedimentation, concentration (24°B), precipitation using ethyl alcohol, vacuum drying and grinding. Physico-chemical properties of pectin powder revealed moisture (10.0%), total ash (1.4%), equivalent weight (652.48), methoxyl content (3.7%), anhydrouronic acid (62.82%), degree of esterification (33.44%), acetyl value (0.68), and jelly grade (80).

Physicochemical Changes in Seven Tomato (Lycopersicon esculentum) Cultivars During Ripening

Seven tomato cultivars were studied for compositional changes during ripening at green, breaker, turner, and ripe stages. Result indicated changes in total soluble solids (4.15 to 6.62 g/100 g), acidity (0.36 to 0.54 g/100 g), reducing sugars (0.76 to 4.04 g/100 g), total sugars (1.67 to 5.52 g/100 g), lycopene in skin (0.07 to 14.28 mg/100 g), and in pulp (0.04 to 6.73 mg/100 g) during ripening from green to red ripe stage. Cultivar UC-828 was found superior with respect to total soluble solids (6.62 g/100 g), reducing sugars (4.04 g/100 g), and total sugars (5.52 g/100 g) where as cultivar 8–2–1–2–5 was found superior with respect to lycopene in skin (14.28 mg/100 g) and in pulp (6.73 mg/100 g). Hunter color values showed a change from negative value of ‘a’ (greenness) to positive values (redness) where as ‘b’ decreased. The (b/a) and tan−1 (b/a) showed a similar pattern of first increased and then decreased. The puncture resistance was decreased from 10.5 to 2.3 N indicating softening during ripening. Correlation studies showed that lycopene content best correlated with Hunter ‘a’ values during ripening (R2 = 0.84 to 0.93). Intercultivar variation in physicochemical parameters at all stages of ripening revealed that Castle Rock was the best cultivar.