Changes in the Quality of Old Apple Cultivars After Freeze-Drying

Abstract

There are several thousand different cultivars of apple trees but only a limited number are cultivated on an industrial scale. Old cultivars can be useful, for example, in the processing industry due to their different composition. In many cases, they have higher organic acid content. The content of mineral components, colour, and polyphenols in the fruit of 7 old apple tree cultivars, growing in the Wolinski National Park, was studied. The changes that occurred in the fruit after freeze-drying were also evaluated. The trees from which the fruit was picked for analysis, despite the lack of chemical protection, were fruiting and the apples had only a few symptoms of damage caused by pests or diseases. The fruit was characterised by a high soluble solids content (14.4-16.4%), in which sugars and especially fructose dominated. The number of organic acids varied greatly and ranged from 0.27 (Oberlander Himbeerapfel) g to 1.07 g/100 g (Winter Goldparmane). The content of polyphenols in fresh apples ranged from 186 mg (Horneburger Pfannkuchenapfel) to 354 mg/100 g (Winter Goldparmane) and increased after freeze-drying from 666 mg (Weisser Winterkalvill) to 1486 mg/100 g (Winter Goldparmane). The dominant group of polyphenolic compounds was phenolic acid. The freeze-drying process caused unfavourable changes in the colour of the pulp. The fruits of Oberlander Himbeerapfel cultivar were most susceptible to these changes. However, the least darkened fruit of Horneburger Pfannkuchenapfel.

Chemical composition and mineral content of fresh and dried fruits of the wild rosehip (Rosa canina L.) population

“…(Radojčin et al, 2021). The content of sugars and organic acids, and especially their ratio in the dried product, is a very important factor in maintaining the quality over some time (microbiological safety), as well as in forming the final taste of the product (Sikora et al, 2020).…”

Pulsed Electric Field Pretreatments Affect the Metabolite Profile and Antioxidant Activities of Freeze− and Air−Dried New Zealand Apricots

“…This highlights the different impacts of freeze drying and air drying on the organic acid composition of fruits. A study on European cranberry found that lyophilized fruit had significantly higher levels of organic acids compared to fruit dried at temperatures of 35–40 °C [ 56 ]. The largest relative difference was observed in the case of ascorbic acid, with the content in the high−temperature−dried fruit averaging 5 mg/100 g of dry matter (DM), representing a 42% decrease compared to the lyophilised material.…”

“…• C [56]. The largest relative difference was observed in the case of ascorbic acid, with the content in the high−temperature−dried fruit averaging 5 mg/100 g of dry matter (DM), representing a 42% decrease compared to the lyophilised material.…”

Effect of drying temperature and storage time on the crispiness of homemade apple snacks

“…Among the various processes used for drying fruit and vegetable chips, the most widely used methods, among others, include hot air drying, 20 air convective drying, 21 freeze‐drying, 22 puffing drying, 2 microwave vacuum drying, 23 vacuum frying 11 . Some processes involve the combination of two or more methods 24,25 .…”

“…19 To predict the diffusional properties of cellular tissues and their behavior during drying, microstructure studies should be conducted, and scanning electron microscopy is a suitable method for achieving this. 2 Among the various processes used for drying fruit and vegetable chips, the most widely used methods, among others, include hot air drying, 20 air convective drying, 21 freeze-drying, 22 puffing drying, 2 microwave vacuum drying, 23 vacuum frying. 11 Some processes involve the combination of two or more methods.…”