Natural Variation Confers ‘Aiyuan 38’ Citrus Mutant a New Color and Unique Flavor

Abstract

Citrus exhibits unique nutritional values. Most citrus cultivars are derived from mutations. However, the effect of these mutations on fruit quality is unclear. We have previously found a yellowish bud mutant in the citrus cultivar ‘Aiyuan 38’. Therefore, this study aimed to determine the effect of the mutation on fruit quality. ‘Aiyuan 38’ (WT) and a bud mutant variant (MT) were used to analyze variations in fruit color variation and flavor substances using colorimetric instruments, high-performance liquid chromatography (HPLC), headspace solid-phase microextraction-gas chromatography–mass spectrometry (HS-SPME-GC–MS), and odor activity values (OAVs). The mutation in MT conferred yellowish characteristics to its peel. Although the differences in total sugar and acid content of the pulp were not statistically significant between WT and MT, the MT glucose content was significantly lower and the malic acid level was significantly higher. HS-SPME-GC–MS analysis revealed that the MT pulp released more types and contents of volatile organic compounds (VOCs) than the WT, whereas the opposite trend was observed for the peel. Analysis of the OAV revealed that the MT pulp contains 6 unique VOCs, whereas the peel contains only 1. This study provides a useful reference for the study of flavor substances associated with citrus bud mutations.

Volatile metabolomics and transcriptomics analyses provide insights into the mechanism of volatile changes during fruit development of ‘Ehime 38’ (Citrus reticulata) and its bud mutant

“…To comprehensively investigate the volatile changes between WT and MT, different developing fruits were subjected to aroma profile analysis. Although MT was clearly distinguished from the orange-colored WT at ripening stages by its yellowish flavedo ( Wang T. et al., 2023 ), there was no visible difference in pulp color between the two varieties during fruit development ( Figure 1A ). HS-SPME-GC-MS was adopted to evaluate the differences in volatiles composition and content of pulps between WT and MT.…”

“…Our previous study has identified a yellow mutant of ‘Ehime 38’ ( Citrus reticulata ) with a richer aroma in pulps relative to the wild type ( Wang T. et al., 2023 ). However, the accumulation patterns of volatile compounds during fruit development in both varieties and molecular mechanism remain elusive.…”

Effects of Exogenous Application of Glycine Betaine Treatment on ‘Huangguoggan’ Fruit during Postharvest Storage

“…The organic acid components (fresh weight) of the pulp were detected by high performance liquid chromatography (LC-1260; Agilent Technologies, Sacramento, CA, USA). Detection of the content of organic acids followed the method described by Wang et al [ 43 ] with slight modifications. The pulp samples were weighed to 0.5 g, ground with pre-chilled 3 mL of 0.2% metaphosphoric acid, fixed to 6 mL, and centrifuged at 4 °C for 15 min at 12,000 r min −1 .…”

Effect of Natural Variation and Rootstock on Fruit Quality and Volatile Organic Compounds of ‘Kiyomi tangor’ (Citrus reticulata Blanco) Citrus

“…Fruit weight was measured by electronic scales and vertical/transverse diameter was measured by vernier calipers. Total soluble solids (TSS) and titratable acids (TA) were measured using a glycolic acid meter (Pocket PAL-BXIACID1; ATAGO, Tokyo, Japan) [54]. V C was measured according to the method described by previous authors [55].…”

“…Headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) was used to extract and detect VOCs in different parts of fruits. Fruit tissues (0.1 g peel and 0.5 g pulp) were ground to a powder using liquid nitrogen and quickly placed in a headspace flask, then 5 mL of saturated sodium chloride solution and 50 µL of 1-hexanol (0.1%, v/v) were added and VOCs were measured after equilibration and extraction [54]. The inlet temperature, desorption time and column chamber warming procedures were performed as previously described [60].…”