A study conducted by Leong and Oey in New Zealand published in Food Chemistry investigated the stability of phytochemicals such as anthocyanins, carotenoids and vitamin C in fruits and vegetables (cherries, nectarines, apricots, peaches, plums, carrots, red bell peppers) when exposed to three different processing conditions (98°C for 10 minutes, -20°C and freeze-drying). Phytochemical-rich fruits and vegetables are believed to have value in the prevention of some chronic diseases. Food processing enables the supply of these commodities outside of their growing seasons.

The aim of the Leong and Oey study was to evaluate the changes in phytochemical content as affected by processing conditions. The researchers reported that the stability of phytochemicals depends on their amount and species, food matrix, the presence of other bioactive compounds in fruits and vegetables, geographical locations of foods, and growth conditions.

The authors concluded that heating and freezing release the anthocyanins bound in plant cell membranes and therefore increase their bioaccessibility. They noticed higher anthocyanins content in heated cherries, peaches and plums (but not in nectarines) compared to fresh fruits. On the other hand heating decreased the carotenoids content in apricots, nectarines and carrots but not in cherries, peaches, plums and red bell peppers. Moreover, in contrast to existing literature the researchers reported that heating inactivates ascorbic acid oxidase that improves the stability of ascorbic acid, with an exception for red bell peppers.

Additionally, the researchers highlighted that heating causes leaching of water-soluble compounds which could change the phytochemical profile and content of fruits in vegetables. Similarly, the rate of freezing may contribute to the changes in phytochemical content.

In the present study freeze-drying as a technique of food processing resulted in a lower phytochemical content when compared to heating and freezing. Thus, in order to achieve high retention of phytochemicals in heated and frozen foods, Leong and Oey propose to heat commodities in sealed vacuum plastic bags and to recover the fruit and vegetables drip loss during thawing.


Published in Applied Research
Copyright © 1998-2022 Chiriotti Editori srl Tutti i diritti riservati
Viale Rimembranza, 60 - 10064 Pinerolo - To - Italy - P.IVA e C.F. 01070350010 - Tel. +39 0121.393127 - email info@foodexecutive.it | Disclaimer