Evaluation of Physiological Characteristics, Soluble Sugars, Organic Acids and Volatile Compounds in 'Orin' Apples (Malus domestica) at Different Ripening Stages.

Shunbo Yang,Yanan Li,Yazhou Yang,Zhengyang Zhao,Zhipeng Meng,Rongxin Chen

doi:10.3390/molecules26040807

Shunbo Yang, Yanan Li + Show 4 more

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https://doi.org/10.3390/molecules26040807

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Abstract

‘Orin’ is a popular apple cultivar, which has a yellow-green appearance, pleasant taste, and unique aroma. However, few studies on the fruit quality characteristics of ‘Orin’ apples have been reported before. In this study, changes of the physiological characteristics were measured at different ripening stages, and the soluble sugars and organic acids were determined by high-performance liquid chromatography (HPLC). Volatile compounds were identified using the headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS). During the fruit ripening, the ‘Orin’ apple fruit weight, size, and total soluble solid were gradually increased by contrast with the titratable acidity, and the firmness decreased. The content of four soluble sugars reached the maximum at the 180 days after full bloom (DAFB) stage. Malic acid was measured as the most abundant organic acid in ‘Orin’ apples. Ethyl butyrate, hexyl propanoate, hexyl acetate and butyl acetate belonging to esters with high odor activity values (OAVs) could be responsible for the typical aroma of ‘Orin’ apples. The aim of this work was to provide information on the flavor characteristics of ‘Orin’ apples and promote this apple cultivar for marketing and processing in the future.

Highlights

Apples (Malus × domestica Borkh.) are one of the most popular fruits and widely planted around the world
We evaluated the physiological characteristics, soluble sugars, organic ac3idosf, 12 and aroma volatile compounds in ‘Orin’ apples at five different ripening stages
The content of four soluble sugars in ‘Orin’ apples generally increased during the fruit ripening periods and reached the maximum at full ripening stage of 180 days after full bloom (DAFB)

Summary

Introduction

Apples (Malus × domestica Borkh.) are one of the most popular fruits and widely planted around the world. Soluble sugars and organic acids directly affect the taste of apple fruits. Soluble sugars are responsible for the sweetness of apple fruits, and organic acids determine the sourness [4]. The content of soluble sugars and organic acids in apples vary among varieties and some other factors such as light, exposure to sun, and other environmental factors could have an impact on it. The synthesis and accumulation of soluble sugars are faster than that of organic acids [6]. Due to the significantly higher sugars/acid ratio, the taste of apple fruits at the ripe stage is much better than the immature fruits [7]. A moderate concentration of organic acids will increase the fruit palatability and quality of apples [6,7]

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