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Hurdle technology applied to prickly pear beverages for inhibiting Saccharomyces cerevisiae and Escherichia coli
Author(s) -
GarcíaGarcía R.,
EscobedoAvellaneda Z.,
TejadaOrtigoza V.,
MartínBelloso O.,
ValdezFragoso A.,
WeltiChanes J.
Publication year - 2015
Publication title -
letters in applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.698
H-Index - 110
eISSN - 1472-765X
pISSN - 0266-8254
DOI - 10.1111/lam.12406
Subject(s) - pear , preservative , food science , potassium sorbate , antimicrobial , chemistry , escherichia coli , horticulture , biology , microbiology and biotechnology , biochemistry , sugar , gene
The effect of pH reduction (from 6·30–6·45 to 4·22–4·46) and the addition of antimicrobial compounds (sodium benzoate and potassium sorbate) on the inhibition of Saccharomyces cerevisiae and Escherichia coli in prickly pear beverages formulated with the pulp and peel of Villanueva (V, Opuntia albicarpa ) and Rojo Vigor ( RV , Opuntia ficus‐indica ) varieties during 14 days of storage at 25°C, was evaluated. RV variety presented the highest microbial inhibition. By combining pH reduction and preservatives, reductions of 6·2‐log 10 and 2·3‐log 10 for E. coli and S. cerevisiae were achieved respectively. Due to the low reduction of S. cerevisiae , pulsed electric fields ( PEF ) (11–15 μ s/25–50 Hz/27–36 kV cm −1 ) was applied as another preservation factor. The combination of preservatives, pH reduction and PEF at 13–15 μ s/25–50 Hz for V variety, and 11 μ s/50 Hz, 13–15 μ s/25–50 Hz for RV , had a synergistic effect on S. cerevisiae inhibition, achieving at least 3·4‐log 10 of microbial reduction immediately after processing, and more than 5‐log 10 at fourth day of storage at 25°C maintained this reduction during 21 days of storage( P > 0·05). Hurdle technology using PEF in combination with other factors is adequate to maintain stable prickly pear beverages during 21 days/25°C. Significance and Impact of the Study Prickly pear is a fruit with functional value, with high content of nutraceuticals and antioxidant activity. Functional beverages formulated with the pulp and peel of this fruit represent an alternative for its consumption. Escherichia coli and Saccharomyces cerevisiae are micro‐organisms that typically affect fruit beverage quality and safety. The food industry is looking for processing technologies that maintain quality without compromising safety. Hurdle technology, including pulsed electric fields ( PEF ) could be an option to achieve this. The combination of PEF , pH reduction and preservatives is an alternative to obtain safe and minimally processed prickly pear beverages with convenient shelf‐life.