Effects of thermal processing and pulp filtration on physical, chemical and sensory properties of winter melon juice

BACKGROUNDWinter melon (Benincasa hispida) is a widely consumed crop in Asia, and believed to impart special benefits to human health. The nutritional composition and sensory properties of four juice types, resulting from a combination of pulp levels (low/high pulp, LP/HP) and thermal processing (with/without boiling, B/NB), LPNB, HPNB, LPB and HPB, were compared. RESULTSThe juices had low sugars (< 20 g kg(-1)) and low titratable acidity (about 2 g kg(-1)). The insoluble solids, glucose, fructose and citric acid content in LP juice were significantly lower than in HP juice. The phenolic amino acids phenylalanine, tyrosine, and tryptophan were detected at 10-45 mg L-1 levels, and the antioxidant activity ranged from 36 to 49 mg gallic acid L-1. C6 and C9 aldehydes were mainly found in HP juice, and boiling induced the accumulation of sulfur compounds and C5 aldehydes. The LPNB juice showed the highest acceptability in the sensory panel. The frozen concentrated orange juice (FCOJ) reconstituted with LPNB was preferable to regular FCOJ for 31% of panelists and not different for 20% of panelists. CONCLUSIONThe low sugar/low acid LPNB juice with fresh' flavor could be developed to replace water for reconstituting FCOJ with enhanced nutritional value. (c) 2016 Society of Chemical Industry