Reduction of Zygosaccharomyces rouxii Population in Concentrated Grape Juices by Thermal Pasteurization and Hydrostatic High Pressure Processing

Abstract

Zygosaccharomyces rouxii is the most frequent spoilage yeast species detected in concentrated grape juice. In order to reduce Z. rouxii populations and consequently extend the microbiological shelf life of this product, different programs of thermal pasteurization and high hydrostatic pressures processing were evaluated. Results showed that pasteurization temperatures higher than 75 °C are necessary to reduce Z. rouxii population in concentrated grape juice. Reduction of 7 logarithms can be reached after 90 s at 75 and 80 °C, and 5 s at 85 °C of pasteurization treatment. High hydrostatic pressure treatment above 500 MPa for 2 min are necessary to reduce 7 logarithms of Z. rouxii population and to significantly extend the shelf life of concentrate grape juice. Extension of holding times from 3 to 5 min, at the different high hydrostatic pressures evaluated, did not improve the Z. rouxii population reduction, nor the shelf life extension of concentrate grape juice. In conclusion, thermal pasteurization and high hydrostatic pressure could be suitable treatments to achieve the reduction of Z. rouxii population below the recommendation limit (10 2 CFU/g) and extension of the microbiological shelf life of concentrate grape juice.

Using High Hydrostatic Pressure Processing Come-Up Time as an Innovative Tool to Induce the Biosynthesis of Free and Bound Phenolics in Whole Carrots

“…Several authors have previously reported that HHP applied at commercial conditions (> 400 MPa, > 3 min) does not affect the total phenolic content in fruits such as strawberry and blackberry (Patras et al 2009a, b), mango (Elizondo-Montemayor et al 2020), tomato and carrot (Patras et al 2009a, b). However, most previous studies evaluating the effect of HHP on phenolics content have been performed in fruit and vegetables processed into pulp or juice prior to HHP treatment with the focus of microbial stabilization (Klug et al 2018;Rojo et al 2019) and enzyme inactivation (Moralesde la Peña et al 2018), and thus there is scarce information on the effect of HHP applied at physiological conditions (come-up time, and pressures below 150 MPa) in whole fresh produce to determine its potential use as an abiotic elicitor of phenolic compounds. Likewise, most previous reports are Fig.…”

Ultrasound-Combined Sterilization Technology: An Effective Sterilization Technique Ensuring the Microbial Safety of Grape Juice and Significantly Improving Its Quality

“…The single treatment volume of the juice was 50 mL, and each treatment was used in at least 3 parallel experiments. For CTS treatment, the grape juice samples were sterilized at 85 °C for 10 min [ 26 ]. The ultrasound-related treatments were based on the method by Liao et al [ 11 ] with minor changes.…”

High Hydrostatic Pressure vs. Thermal Pasteurization: The Effect on the Bioactive Compound Profile of a Citrus Maqui Beverage

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