Hot Air Treatment and its Effect on Nectarine Metabolism var. Big Top Stored at Different Temperatures

Victor David González López,Eva Torres,Yanina Pariani Marrero,Ana Cecilia Silveira,Vanessa Cuozzo Rucci

doi:10.31285/agro.23.95

Abstract

The effect of hot air treatment (35 °C / 36 h) on Big Top nectarines prior storage at 0 and 5 °C for 6, 18 and 27 days followed by 6 days at 20 °C (shelf life, sl) was evaluated. Respiratory activity was twice as much in fruits at 5 °C (24 mg CO2 kg-1h-1), compared to those kept at 0 °C during the respiratory peak. At 0 °C, the treated fruits showed between 2 and 5 % more respiratory activity. The total polyphenols were not affected by temperature or treatment (0.22 and 0.24 mg galic acid equivalent g-1 fw) but almost doubled in sl, especially in fruits from 0 °C. At some analysis moments, the total antioxidant capacity of untreated fruits stored at 0 °C (0.42 and 0.45 mg equivalent ascorbic acid g-1 fw) doubled the values of the treated ones, although this situation was reversed in sl. The superoxide dismutase activity was considerably higher in fruits treated and stored at 0 °C (15-30 units of activity mg-1 of protein), as opposed to the observed at 5 °C. The activity of polygalacturonase and pectinmethyl esterase, as well as the development of mealiness in sl and in untreated fruits from 5 °C, would indicate that the heat treatment had a protective effect reducing the occurrence of damage. However, the little or no response observed in other variables make it necessary to confirm the effect of heat treatment in future studies.

Highlights

Peach and nectarine production in Uruguay is of around 12,858 and 1,550 tons, which covers an area of 1,388 and 160 ha, respectively, exploited by 600 producers and destined 97 % to the domestic market, 2.8 % to industry and 0.2 % for export(1).Both fruits are of the climacteric type, which determines their fast deterioration after harvest if they are kept at room temperature (15-20 °C), due to the increase in the rceosldpisratotorarygerahteasabnedeenthuysleedneaspraotdouoclttioonex(Cte2nHd4)s.hTehlfelrifeef(o2)r(e3)
This study aimed to evaluate the effect of hot air treatment on metabolic activity and the enzymatic and non-enzymatic antioxidant systems of nectarine fruit, Big Top variety, preserved at two temperatures, one considered optimal (0 °C) and another considered stressful (5 °C)
In other cold-sensitive products, such as the Micro-Tom tomato, this behavior was observed, where respiration was higher after 28 days at 4 °C compared to when it was stored at a higher temperature(28)

Summary

Introduction

Peach and nectarine production in Uruguay is of around 12,858 and 1,550 tons, which covers an area of 1,388 and 160 ha, respectively, exploited by 600 producers and destined 97 % to the domestic market, 2.8 % to industry and 0.2 % for export(1). Both fruits are of the climacteric type, which determines their fast deterioration after harvest if they are kept at room temperature (15-20 °C), due to the increase in the rceosldpisratotorarygerahteasabnedeenthuysleedneaspraotdouoclttioonex(Cte2nHd4)s.hTehlfelrifeef(o2)r(e3),. In the case of Big Top, Candir and others(8) indicate that they have a conservation potential of 30 days at 0 °C, followed by 2 days of SL at 20 °C

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