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Abstract The aim of the present study was to determine the effect of high hydrostatic pressure (HP) and films activated with a combination of enterocin AS-48 and thymol (AF) on the microbial load and bacterial diversity of fruit puree (banana, apple, pear). HP and AF were applied singly, or in combination (AFHP). Samples were chill-stored. HP and AFHP treatments reduced viable counts significantly (P ≤ 0.05). The predominant bacterial groups in the puree were fam. Comamonadaceae (23.17%) and genera Methylobacterium (21.46%), Acidovorax (8.70%) and Sphingomonas (6.63%). Pseudomonas became relevant by the end of storage (10.50%). Most of the AF samples had higher relative abundances of Comamonadaceae, Methylobacterium, Acidovorax and Sphingomonas and lower relative abundance of Pseudomonas. Application of HP treatment markedly reduced the relative abundances of Comamonadaceae , Methylobacterium , Acidovorax and Sphingomonas. Lactobacillales increased in relative abundance upon application of HP treatment but not during storage, while Pseudomonas increased towards the end of storage. The combined treatment (AFHP) achieved greatest reduction in the relative abundances of Comamonadaceae and Methylobacterium. Results indicate that AFHP treatment had greatest effects on the bacterial diversity of the fruit puree and was also the most effective in keeping total aerobic mesophiles and Enterobacteriaceae below detectable levels. Highlights • The bacterial diversity of fruit puree was affected by treatments. • Main groups were Comamonadaceae, Methylobacterium , Acidovorax and Sphingomonas. • Active packaging increased the relative abundance of main bacterial groups. • High pressure treatment decreased the relative abundance of main bacterial groups. • Combined treatments caused greatest inactivation and changes in bacterial diversity. [ABSTRACT FROM AUTHOR]

The effect of storage temperature on the degradation of total phenolic content (TPC) and antioxidant activity in hardy kiwifruit ( Actinidia arguta ) puree was investigated at temperatures of 5, 15, 25, and 45 °C for 72 h. An increase in the storage temperature resulted in a decrease in the TPC and antioxidant activity of hardy kiwi puree over time. The degradation of total phenolic content and antioxidant activity followed a first-order kinetic model and the kinetic parameters such as k , t 1/2 , Q 10 , and Ea were calculated. The k and t 1/2 values decreased with increasing storage temperature and the Q 10 values for TPC and antioxidant activity were 1.43 and 1.43, respectively. These results indicated strong dependence on temperature of phenolic content and antioxidant activity in hardy kiwi puree. The Ea for the degradation of TPC and antioxidant activity in hardy kiwi puree were 28.15 and 29.07 kJ/mol, respectively. Major phenolic compounds in hardy kiwi identified by UPLC-Q-TOF MS were epicatechin, procyanidin B type, procyanidin trimers, catechin, chlorogenic acid, and isoquercetin. These compounds were degraded with increase in storage temperature and time. This result is consistent with kinetic studies on phenolic content and antioxidant activity. [ABSTRACT FROM AUTHOR]

Abstract: Fruit purees, combined or not with polysaccharides, have been used in some studies to elaborate edible films. The present study was conducted to evaluate tensile properties and water vapor barrier of alginate-acerola puree films plasticized with corn syrup, and to study the influence of cellulose whiskers from different origins (cotton fiber or coconut husk fiber, the latter submitted to one- or multi-stage bleaching) on the film properties. The whiskers improved the overall tensile properties (except by elongation) and the water vapor barrier of the films. The films with coconut whiskers, even those submitted only to a one-stage bleaching, presented similar properties to those of films with cotton whiskers, despite the low compatibility between the matrix and the remaining lignin in coconut whiskers. This was probably ascribed to a counterbalancing effect of the higher aspect ratios of the coconut whiskers. [Copyright &y& Elsevier]

Oxygen is a key factor in fruit pure´es browning. The use of a commercial glucose oxidase–catalase enzyme system (GOX) for oxygen removal and browning control of Golden Delicious apple and Kaiser pear pure´es during storage has been investigated. The effect of ascorbic acid and peroxidase has also been tested and results compared with control (no treatment). Colour change was quantified using the CIE L*, a*, b* system. Heating has been the unique treatment able to control the enzymatic browning of fruit pure´es, whereas GOX was the most efficient in reducing to low level the dissolved oxygen content in apple and pear pure´es (99% oxygen removed), and showed an interesting capability to control the nonenzymatic browning during fruit processing and pure´es storage. However, ascorbic acid decreased the nonenzymatic browning of fruit pure´es to a larger extent than any other chemical treatment used in this study. The Kaiser pear shows a fast enzymatic browning thus may represent a good ‘standard’ to measure browning kinetics. [Copyright &y& Elsevier]