High pressure and thermal processing on the quality of zucchini slices

Abstract

In response to the market demand for low processed vegetables, high-pressure treatments (400,600 MPa; 1,5 min) were applied on zucchini slices and compared to a traditional blanching treatment. Histological observations, texture and color analysis, pectinmethylesterase (PME) and antioxidant (DPPH) activities were measured and compared to untreated samples. The histological observations revealed that the longer high-pressure treatments (5 min) led to more extended cell lysis and dehydration than the shorter ones (1 min) and blanching. High-pressure treatments resulted less effective than blanching on PME inactivation, with the best results obtained at 400 MPa for 1 min. Comparable texture parameters were observed for high-pressured and blanched samples. The negative correlation found between PME activity and the texture parameter ‘distance of the first peak force’ revealed an effect of PME on the texture recovery after treatments. High pressure led to a general browning of zucchini parenchyma and to DPPH drop. The correlations found between DPPH and color suggest the common nature of the phenomena. The influence of pressure and time on the studied parameters was revealed by two-way ANOVA. Principal component analysis clustered together the four high-pressure-treated samples, being clearly divided by blanched and untreated ones.

Understanding the Impact of High-Pressure Treatment on Physico-Chemical, Microstructural, and Microbiological Aspects of Pumpkin Cubes

“…In HPP200, few changes were observed ( Figure 1 B), mainly related to the decrease in cell turgor (dehydration-d) and some cells showed signs of cell detachment (cd). Several authors reported an increase in cell wall thickness (cwt)-swelling, cell damage (cd), and dehydration (d) after pressure treatments on different fruits and vegetables [ 14 , 21 , 26 , 34 , 35 , 36 ].…”

“…After the treatment with a pressure of HPP500 ( Figure 1 E), the parenchyma cells showed plasmolysis, gaps, and increased cell wall thickness (cwt). Several authors [ 14 , 37 , 38 , 39 ] hypothesized that cells separation was due to the breakage of chemical bonds between the pectic components of the middle lamellae of adjacent cells and/or to the hydrolysis of some other components of the cell wall such as pectin, hemicelluloses, and cellulose.…”

“…For the processing and preservation of fruits and vegetable products, many conventional thermal processes were applied. Although these treatments are essential to stabilize the product, they could negatively modify the physico-chemical and organoleptic characteristics [ 10 , 11 , 12 , 13 , 14 ]. One of the alternative emerging non-thermal technologies readily accepted by consumers is high-pressure processing (HPP) [ 15 ].…”

Emerging Postharvest Technologies to Enhance the Shelf-Life of Fruit and Vegetables: An Overview

“…Moreover, the stimulation and accumulation of nutraceutical compounds were also observed. The effects of HHP application have been reported for different minimally processed horticultural commodities [ 31 , 32 , 34 , 37 ], whole produce [ 30 , 35 , 36 , 46 ], and juice [ 54 ], demonstrating great efficiency in improving food safety aspects and in maintaining quality.…”

The Effect of Different Organic Foliar Fertilization on Physiological and Chemical Characters in Hop (Humulus lupulus L., cv Cascade) Leaves and Cones

“…The parameters were quantified using the application software provided (Texture Exponent for Windows, version 6.1 10.0). Ten samples of each treatment at each time of sampling were analyzed [27].…”