This study evaluated the effect of jam processing of cherry on the phytochemical and physiochemical properties for fresh cherry, after processing and during 15 days at 25, 35, 45 and 55C. Fresh cherry had the highest contents of total phenolics, antioxidant activity and anthocyanins. Jam processing significantly decreased total phenolics (370.20 mg gallic acid equivalent/100 g), antioxidant activity (50.72%) and anthocyanins (6.53 mg cyanidin‐3‐glucoside/100 g). During jam storage, also, a significant decrease of these compounds was observed at studied temperatures. Color measurements of jam during storage showed an increase of lightness and yellowness and a decrease in redness in cherry only after processing. Total color differences and chroma values increased after processing from 21.36 to 31.01 and from 10.67 to 14.32, respectively, and during storage for 15 days. Q10 values of phytochemicals were between 1 and 2 and were less sensitive to temperature changes as compared with most chemical and biochemical reactions.
Cherry fruits contain high levels of phenolic compounds, anthocyanins and antioxidants as much as numerous other biological properties such as vitamins and minerals, these compounds have the ability to reduce the risk of many diseases such as heart diseases and cancer. There is a considerable demand for fresh fruits as well as their products. Because many types of fruit are seasonal and their shelf life is limited, they must be processed to keep the quality. Processing may include preservation by several methods as addition of sugar to make a jam. Variability in the levels of protective components in fruits is affected by several factors, in particular, postharvest processing as jam making. These variations may affect the final concentration of physiochemical properties, phenolic compounds, antioxidants and anthocyanins in fruits and their eventual bioactivity; these components in processed jam are affected by temperature, fruit maturation and presence of light.