|ABOELHAGGAG, RAMADAN - Egypt National Research Center|
|GUO, MINGMING - Zhejiang University|
Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/20/2021
Publication Date: 8/10/2021
Citation: Jin, Z.T., Aboelhaggag, R.M., Guo, M. 2021. Juice preservation using combined nonthermal processing and antimicrobial packaging. Journal of Food Protection. 84(9)1528-1538. https://doi.org/10.4315/JFP-21-035.
Interpretive Summary: Heat treatment could negatively impact on sensory and nutritional values of fruit juices, hence, nonthermal food processing could be a better alternative solution for juice preservation. This study was to investigate the effectiveness of pulsed electric fields (PEF), pulsed ultraviolent light (PL), and antimicrobial packaging (AP) treatments, either individually or combined, in reduction of microbial populations and in maintaining the quality of fruit juices. These results from this study indicated that the combined treatments were effective in reducing microbial levels in juices without causing changes in their physiochemical properties, quality, and shelf-life. Specifically, the combined treatments reduced 99.999% of Escherichia coli and natural microflora populations. Storage studies showed that PEF, AP and PEF+AP treated apple and orange juices had quality stability for 5 weeks at 10 degree C. This study provides valuable information to juice processors for consideration and design of nonthermal pasteurization of juice products.
Technical Abstract: This study was to investigate the effectiveness of pulsed electric fields (PEF) treatment, pulsed UV light (PL) treatment, and antimicrobial packaging (AP) treatment, either individually or combined, in reduction of microbial populations and in maintaining the quality of fruit juices. Apple or orange juice samples inoculated with E. coli K12 or native mold and yeast (M&Y) were treated by bench scale PEF and/or PL processing systems and stored in glass jars with antimicrobial caps containing 10 µl of carvacrol (AP). The reduction in microbial populations and the physicochemical properties of juice samples were determined after treatments and during storage at 10°C. Treatment conditions were PL (5 to 60 s; 1.04 J/cm2/s), PEF (19, 23, 30 kV/cm), PEF followed by PL (PEF+PL), PL followed by PEF (PL+PEF), and PEF+PL+AP. Populations of E. coli in the control, PL, PEF, PL+PEF, and PEF+PL samples were 7.8, 7.0, 4.8, 3.9, and 3.6 log/ml, respectively, after treatments. There were no significant (p>0.05) differences between the PL+PEF and PEF+PL treatments; both treatments reduced E. coli populations to non-detectable levels (> 5 log reduction) after 7 days. Both PEF+PL and PEF+PL+AP treatments achieved over 5 log reduction of M&Y, however, juice samples subject to PEF+PL+AP treatment had lower M&Y counts (2.9 log) than samples subject to PEF+PL treatment (3.9 log) after 7 days. There were no significant differences in pH, acidity, total soluble solid contents among all samples after treatments. Increased PL treatment times reduced color a*, b* values, total phenolics and carotenoid contents. Storage studies showed that PEF, AP and PEF+AP treated apple and orange juices had quality stability for 5 weeks at 10°C. This study provides valuable information to juice processors for consideration and design of nonthermal pasteurization of juice products.