The postharvest life of flat peach fruit is limited by the appearance of chilling injury symptoms, especially internal browning. In this study, impacts of the exogenous application of proline (0, 5, 10, and 15 mM) and L-cysteine (0, 0.2, 0.4 and 0.6%) on attenuating chilling injury of flat peach fruit were evaluated all over the cold storage. The results demonstrated that the fruits treated with 15 mM proline and 0.4 % L-cysteine showed lower levels of internal browning and these treatments prevented the excess enhancement of total soluble solids (TSS), the decline of titratable acidity (TA) content and the loss of fruit firmness during storage time. A lower accumulation of hydrogen peroxide (H2O2), malondialdehyde (MDA), electrolyte leakage, and higher activity of antioxidant enzymes, along with higher ascorbic acid content and antioxidant capacity, were observed in treated fruits. Treated fruits also showed higher activity of phenylalanine ammonia lyase (PAL) and conversely lower activity of polyphenol oxidase (PPO), which led to a higher accumulation of total phenols and flavonoids. Moreover, a higher accumulation of endogenous proline was observed in 15 mM proline treated fruits. Eventually, according to our results, the exogenous administration of proline and L-cysteine as safe, natural and environmentally friendly treatments, preserved the nutritional quality of flat peach fruits during long-term cold storage.

The main purpose of cold storage of fruits and vegetables is to maintain their nutritional and sensory values during their long-term postharvest life (Aghdam et al., 2018). However, the high sensitivity of tropical and subtropical crops such as pomegranate fruits (Punica granatum L.) to low temperatures limits the applicability of cold storage (Sayyari et al., 2016). Storage of pomegranate fruits at a low temperature (5°C or lower) is limited by some disorders, for example, browning, scaled, and pitting as the main symptoms of chilling injury (CI) (Pareek et al., 2015). Therefore, in various trials, several treatments have been tested to enhance chilling tolerance and decrease CI symptoms in pomegranate fruits, including salicylic acid (Sayyari et al., 2009), salicyloyl chitosan (Sayyari et al., 2016),

High content of dietary and health beneficial compounds such as sugars, ascorbic acid, amino acids, anthocyanin, minerals, pectin, fibers, and above all polyphenolic flavonoids along with antioxidant activity is the most crucial reason of increasing the pomegranate (Punica granatum L.) production and consumption around the world (Palou et al., 2007;Pareek et al., 2015). Pomegranate is a non-climacteric fruit that does not ripen after picking up even with ethylene treatment (Elyatem & Kader, 1984). However, physiological and biochemical alterations are continued after harvesting and decreases the quality of harvested fruit. Due to this, the harvested