The effect of PEF pre-treatment prior to osmotic dehydration on mass transfer parameters, colour, antioxidant and antimicrobial properties in organic strawberries and kiwifruits was evaluated. An increase of water loss in both fruits upon the application of combined processes was noticed (up to 21.6%), while a decrease of solid gain was observed only in kiwifruit samples dehydrated in sucrose (about 45%). In general, the combined treatments were beneficial for colour maintenance in both fruit tissues. The antioxidant capacity (DPPH) and activity (ORAC) increased after PEF treatment, however, all the combined treatments reduced significantly these values (of about 20 and 28% for strawberry and of about 56 and 35% for kiwifruit, respectively for DPPH and ORAC methods). In general, PEF treatment alone was also effective with regard to an increase in the antimicrobial activity of the samples against the tested microorganisms (B. subtilis, E.coli, S. cerevisiae).

Industrial relevance

PEF pre-treatment coupled with osmotic dehydration could be applied at industrial level to obtain semi-dried fruit products. Moreover, both processes could be used as pre-treatments for drying process, in order to develop healthy and microbiologically stable fruit snacks. In fact, in the present work we observed that PEF pre-treatment alone promoted higher antioxidant and antimicrobial activity. The combined process decreased both parameters, suggesting that an accurate study is necessary to evaluate the benefits of these processes in terms of bioactive compounds retention and time and energy consumption in further drying process. The results of the present study could be used as a starting point for the industries to design novel products with intermediate moisture content intended for further processing.

中文翻译：

---

PEF辅助渗透脱水的有机水果的抗氧化和抗菌性能

评估了渗透脱水之前的PEF预处理对有机草莓和奇异果中传质参数，颜色，抗氧化剂和抗菌性能的影响。注意到采用组合工艺后，两种水果的水分流失都增加了（高达21.6％），而仅在蔗糖中脱水的奇异果样品中观察到了固体增加的减少（约45％）。通常，组合处理有利于两个水果组织的颜色保持。PEF处理后抗氧化能力（DPPH）和活性（ORAC）增加，但是，所有联合处理均显着降低了这些值（草莓分别为DPPH和ORAC的大约20％和28％，猕猴桃分别为大约56和35％方法）。一般来说，枯草芽孢杆菌，大肠杆菌，酿酒酵母）。

行业相关性

PEF预处理与渗透脱水相结合可用于工业生产半干果产品。而且，这两种方法都可以用作干燥过程的预处理，以开发健康和微生物稳定的水果零食。实际上，在目前的工作中，我们观察到单独的PEF预处理可以促进更高的抗氧化剂和抗菌活性。组合过程降低了两个参数，这表明需要准确的研究来评估这些过程在进一步干燥过程中的生物活性化合物保留率，时间和能量消耗方面的益处。本研究的结果可作为工业设计具有中等水分含量的新型产品的起点，以用于进一步加工。