Freeze concentrated apple juice maintains its flavor

Tsuyoshi Yoda,Hiroshi Miyaki,Tomoaki Saito

doi:10.1038/s41598-021-92274-0

Tsuyoshi Yoda, Hiroshi Miyaki + Show 1 more

Open Access

https://doi.org/10.1038/s41598-021-92274-0

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Abstract

Concentrated juices are sources of alcoholic drinks. Juice concentration may be achieved using different methods, such as freezing or heating. High temperatures in the process of juice concentration damage heat-sensitive components, such as aromatic compounds. Although the freezing process of juice concentration has been studied, analyses have been inadequate, particularly in addressing flavors. Therefore, we investigated the characteristics of freezing and heating during apple juice concentration in the context of flavor. We found that a total of 97 compounds were found in fresh juice, and freeze-concentrated juice retained 57 of these compounds. Interestingly, freezing led to the generation of 37 flavor compounds. Furthermore, people had difficultly differentiating between intact and frozen concentrated juice. The ratios were almost same between those who correctly identified (28%) and those who incorrectly identified fresh and reconstituted freeze-concentrated juice (25%). We discuss the mechanisms of flavor generation on freezing concentration with regard to the increases in enzymatic activity or other causes. Our study showed that the methods of juice concentration that utilize freezing retain flavor better. These data will benefit juice concentration processes of apples and other fruits in the future.

Highlights

Concentrated juices are sources of alcoholic drinks
Juices are usually concentrated by heating evaporation; the high temperatures used in these processes are known to damage heat-sensitive components and reduce the quality of the juice[4]
Sugar was added to the juice to reach 13.9% because the sugar content of apple juice fluctuates depending on seasonal changes and the type of apples[21]

Summary

Introduction

Concentrated juices are sources of alcoholic drinks. Juice concentration may be achieved using different methods, such as freezing or heating. High temperatures in the process of juice concentration damage heat-sensitive components, such as aromatic compounds. Our study showed that the methods of juice concentration that utilize freezing retain flavor better. These data will benefit juice concentration processes of apples and other fruits in the future. Juices are usually concentrated by heating evaporation; the high temperatures used in these processes are known to damage heat-sensitive components and reduce the quality of the juice[4]. Human tasting is used for quality control of apple juice[14], and its concentrated form is often used to study its q uality[15,16] Both chemical analysis evaluation and sensing examination of cryoconcentrated juice by humans have been r eported[17,18]. The cryoconcentration process does not significantly affect the sensory evaluation r esults[18]

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