Effect of extraction condition on properties of pectin from banana peels and its function as fat replacer in salad cream

摘要

Banana peels are wasted from banana processing industry. Pectin is a soluble dietary fibre usually prepared from fruit and vegetable processing wastes. Pectin extraction from banana peels thus should be an effective way of waste utilization. This study aimed to determine the effect of extraction condition on the properties of pectin from peels of Nam Wa banana (Musa (ABB group) ‘Kluai Nam Wa’) and its role as fat replacer in salad cream. Banana peel pectin (BPP) was extracted with HCl (pH 1.5) and water (pH 6.0) for 30–120 min at 90 ± 5 °C. Acid extraction yielded 7–11% pectin on a dry basis with galacturonic acid content (GalA), degree of methylation (DM), and viscosity-average molecular weight (Mv) of 42–47, 57–61%, and 17–40 kDa, respectively; while water-extracted BPP contained lower DM but higher GalA and Mv. Prolonged extraction raised the pectin yield but lowered the Mv of BPP and the viscosity of their solutions. Incorporation of BPP obtained from 60 min acid- and water-extraction into salad cream at 30% oil substitution level resulted in the decreases in viscosity and lightness. All reduced-fat samples were stable to cream separation during 3-weeks storage although the formula containing water-extracted BPP had larger oil droplet size and greater extent of droplet flocculation. There was no difference in sensory scores rated by 50 panelists on thickness, smoothness, and overall acceptability of the full- and reduced-fat salad creams. Therefore, Nam Wa banana peels can be an alternative source of pectin with potential application as fat replacer in food products.