Effect Of Coating With Oxidized Starch On Postharvest Quality Of Strawberry,Sweet Cherry And 'Barrtlett'Pear

Strawberries, sweet cherries and ‘Bartlett' pears are the major fruits during the summer in Northern of China. However, these fruits have a shorter shelf life, and easy to decay and quality breakdown during postharvest. In this study, oxidized starch was used for coating fruit of strawberries, sweet cherries and ‘Bartlett' pears, the changes of postharvest physiological and quality parameters were determined on ethylene production, respiration rate, weight loss, firmness, color etc. Meanwhile, the chlorophyll synthesis and degradation of ‘Bartlett' pears were also analyzed. Results showed as:1. Oxidized starch coating effectively suppressed ethylene production, respiration rate and malondialdehyde(MDA) content in strawberry fruit, reduced the weight loss, maintained firmness, content of total soluble solids(TSS), titratable acidity(TA), ascorbic acid and anthocyanin in fruit. The treatment significantly inhibited the decay of fruit during storage.2. Sweet cherries coated with oxidized starch had less ethylene production, respiration rate, membrane permeability and MDA content. The treatment reduced the weight loss, maintained firmness, and content of TSS, TA and ascorbic acid of fruit during storage.3. Coating with oxidized starch effectively inhibited the ethylene production, respiration rate and MDA content, decreased weight loss, maintained firmness, content of TSS and TA, kept a better color of ‘Bartlett' fruit during storage.4. Coating improved the accumulation of precursors of chlorophyll synthesis in ‘Bartlett' fruit, such as ?-aminolevulinic acid, porphobilinogen, Mg-protoporphyrin IX, protoporphyrin IX. The treatment enhanced the content of chlorophyll a, chlorophyll b and total chlorophyll, inhibited activity of chlorophyll enzyme and Mg-dechelation. Coating treatment had a higher the chlorophyll content in fruit during storage.It is suggested that fruit coated with oxidized starch could delay process of fruit mature and senescence by inhibiting ethylene release and respiration rate. The treatments effectively maintain the quality of strawberries, sweet cherries and ‘Bartlett' pears during storage. Moreover, coating keeps green color of ‘Bartlett' peel by adjusting chlorophyll synthesis and degradation.