Delso Carlota, Berzosa Alejandro, Sanz Jorge, Álvarez Ignacio, Raso Javier
Food Technology, Facultad de Veterinaria, Instituto Agroalimentario de Aragón-IA2, Universidad de Zaragoza-CITA, 50013 Zaragoza, Spain.
Foods. 2022 Feb 21;11(4):621. doi: 10.3390/foods11040621.
This study's aim is to evaluate Pulsed Electric Fields (PEF) technology as an alternative method for the processing of red grape juice. For this purpose, two PEF treatments were applied: first to grapes for polyphenol enrichment of the juice, and subsequently for microbial decontamination of the obtained juice. Juice obtained from PEF-treated grapes (5 kV/cm, 63.4 kJ/kg) had the polyphenol content 1.5-fold higher and colour intensity two times higher of control juices by spectrophotometric measurement ( ≤ 0.05). A subsequent decontamination treatment by PEF (17.5 kV/cm and 173.6 kJ/kg) achieved inactivation of the present microbiota (yeasts, moulds, and vegetative mesophilic bacteria) below detection level (<30 CFU/mL). Furthermore, PEF-treated juices were microbiologically stable up to 45 days, even at abusive refrigeration storage temperatures (10 °C). PEF juice quality and sensory characteristics were similar to a fresh juice; they were neither affected by the PEF decontamination treatment, nor by storage time and temperature. Results obtained in this study demonstrate the considerable potential of PEF for the production of a polyphenol-enriched and microbially stabilized red grape juice as a unique and sustainable alternative for the juice industry, while avoiding enzymatic and heat treatments.
本研究的目的是评估脉冲电场（PEF）技术作为加工红葡萄汁的替代方法。为此，进行了两种PEF处理：首先对葡萄进行处理以富集果汁中的多酚，随后对所得果汁进行微生物去污处理。通过分光光度法测量（≤0.05），经PEF处理的葡萄（5 kV/cm，63.4 kJ/kg）所获得的果汁中多酚含量比对照果汁高1.5倍，颜色强度高两倍。随后通过PEF（17.5 kV/cm和173.6 kJ/kg）进行的去污处理使现有的微生物群（酵母、霉菌和嗜温性营养细菌）失活至检测水平以下（<30 CFU/mL）。此外，经PEF处理的果汁在长达45天的时间内微生物学稳定，即使在恶劣的冷藏储存温度（10°C）下也是如此。PEF处理的果汁质量和感官特性与新鲜果汁相似；它们既不受PEF去污处理的影响，也不受储存时间和温度的影响。本研究获得的结果表明，PEF在生产富含多酚且微生物稳定的红葡萄汁方面具有巨大潜力，这是果汁行业一种独特且可持续的替代方法，同时避免了酶处理和热处理。
