Chemical Composition, Physicochemical and Technological Properties of Selected Fruit Peels as a Potential Food Source

Fruits after processing leave large proportion of peels, which is a nuisance to the environment as a solid waste. The aim of this study was to ascertain the chemical composition, physicochemical properties, and technological properties of selected such fruit peels to determine their suitability for use as natural food ingredients. Peels from four fruit varieties namely pineapple (PP), orange (OP), yellow passion fruit (PFP) and avocado (AP) were collected from fruit waste of Sri Lankan food industries. Proximate compositions of those were analyzed by AOAC approved methods in dry matter basis. Bulk density (BD), color values (L*, a*, b*), water-holding capacity (WHC), oil- holding capacity (OHC), emulsifying Capacity (EC), emulsifying stability (ES), least gelation concentration (LGC), foaming capacity (FC) and foaming stability (FS) of the peel powders were evaluated by using appropriate physical and chemical tests. All the readings were taken in triplicates. The results showed that AP and OP are rich sources of lipids while all the peels are rich in crude fibers. PFP showed significantly high WHC (99.00 +/- 0.00%) as well as prominent OHC (30 +/- 0.00%) and SC (16.94 +/- 0.47). OP and PP can contribute as good bulking agents. Whereas, AP observed weak gelling and foaming abilities. Color values of four peels were significantly different. These results confirmed the utilization of peels of desired physicochemical and technological properties as sources of food fibers or bulk ingredients in food applications requiring oil and moisture retention. Among studied fruit peels PFP having good potential for use as excellent food hydrocolloid.