Application of fuzzy logic technique for sensory evaluation of high pressure processed mango pulp and litchi juice and its comparison to thermal treatment

摘要

Sensory attributes of high pressure processed (200, 400, and 600 MPa/20, 27 (ambient temperature), 40 and 60 degrees C/10 min (fixed)) mango pulp (Mangifera indica cv. Amrapali) and litchi juice (Litchi chinensis cv. Bombai) were evaluated and compared with untreated and thermally treated (0.1 MPa/95 degrees C/10 min) samples using fuzzy logic. A semi-trained panel of judges analyzed the samples for various sensory attributes viz., color, aroma, body, taste, aftertaste, mouthfeel, and appearance. Judges' preference on the importance of sensory attributes was obtained as crisp numbers instead of linguistic variables, using the 5-point fuzzy logic scale. Sensory quality of samples was then compared based on estimated overall sensory scores, overall membership function, similarity values, ranking of the samples, and quality attributes. The sensory attributes of mango pulp and litchi juice were found to be dependent on product type and process severity. In general, high pressure processed samples had higher likeness than their thermally processed counterparts. The sensory acceptance of high pressure treatment was similar to fresh litchi juice, irrespective of the applied pressure/temperature level, whereas severe deterioration was observed after thermal treatment In case of mango pulp, 600 MPa/60 degrees C emerged as the upper boundary limit beyond which HPP considerably affected the sensory attributes of the product, whereas no such effect was seen in litchi juice. Among the tested attributes, "taste" was adjudged extremely important sensory characteristic for both mango pulp and litchi juice. Further, the changes in sensory attributes of both fruit products upon processing were correlated to changes in physico-chemical parameters, viz., color, pH, total soluble solids and phenolics content.