Optimization of pretreatment for quality maintenance of fresh cut salad vegetables under refrigeration conditions
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Date
2021
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Punjab Agricultural University, Ludhiana
Abstract
Five different disinfectants viz. sodium hypochlorite, potassium metabisulfite, citric acid, acetic
acid and benzoic acid were evaluated over fresh cut salad vegetables (cucumber, carrot and
tomato) to check their bactericidal efficacy. Amongst five disinfectants evaluated, sodium
hypochlorite showed maximum microbial reduction of 49.99-56.51% Total Plate Count, 47.0566.66%
Yeasts & Moulds and 51.27-70.83% coliforms with respect to control on fresh cut
cucumber, carrot and tomato. Optimization of sodium hypochlorite concentration revealed
maximum decrease in microflora @ 200 ppm. However, 100 & 150 ppm concentration levels
also showed decrease in microbial reduction upto acceptable limits with non-significant
difference at both concentrations. Considering residual chlorine level in fresh cuts and
microbial reduction, 100 ppm concentration was optimized for the study. Further, optimization
of pretreatment temperature, pH and contact time was statistically designed and analyzed using
response surface methodology. Numerical optimization of results revealed a temperature of 6.5,
10.0 and 6.5°C; pH 6.0, 7.0 and 7.0; contact time 23.0, 8.0 and 30.0 minutes was found to be
optimized for fresh cut cucumber, carrot and tomato disinfectant pretreatment with a
desirability level of 94, 94 and 92%, respectively. Validation of results was done at 3Kg scale
under all optimized conditions. Shelf life analysis of pretreated (under all optimized conditions)
and untreated fresh cut vegetables stored under refrigeration conditions (5-7°C) revealed
enhancement in shelf life of treated fresh cut vegetables from 6, 9 and 6 days to 9, 12 and 9
days of fresh cut cucumber, carrot and tomato, respectively. During shelf life period, all
physicochemical parameters of pretreated fresh cut vegetables differed non-significantly along
with microbial load under acceptable limits and a good sensory score.
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Citation
Gurliin (2021). Optimization of pretreatment for quality maintenance of fresh cut salad vegetables under refrigeration conditions (Unpublished M.Sc. thesis). Punjab Agricultural University, Ludhiana, Punjab, India.