TA is directly related to the concentration of organic acid present in fruit. AITC treatment evidently reduced TA loss, whereas the control fruit exhibited a considerable reduction in TA during storage (Fig. 4B). Chen et al. (2011) reported that fresh mulberry fruit showed a decreasing tendency in TA value during storage at −1 °C. TA loss of mulberry fruit could be reduced by H2S treatment (Hu et al., 2014). The changes in TA and TSS contents could be associated with the metabolic activity and respiratory rates of fruits. The significant difference (P < 0.05) in TSS and TA contents between the control and AITC treated fruit could be explained by a lower respiration (Fig. 3), which caused less depletion of sugars and acids when the fruit were treated with AITC.
3.5. Effect of AITC treatment on MDA content and LOX activity of mulberry fruit
MDA content and LOX activity are often used as measurements of loss of membrane integrity of fruits in response to stress during postharvest storage (Yang et al., 2009 and Ma et al., 2014). As shown in Fig. 5A, MDA content in control fruit gradually increased during storage and reached the maximum value of 1.67 mmol kg−1 of fresh weight on day 9, and then decreased to 1.24 mmol kg−1 of fresh weight on day 12, with the values in AITC-treated fruit consistently lower than that of the control. At the end of 15-day storage, the MDA levels of fruit treated with AITC at 5 and 15 μL L−1 were 63.7% and 65.3%, respectively, lower than that of the control fruit.