Influence of green banana pulp on the rheological behaviour and chemical characteristics of emulsions (mayonnaises)

The influence of green banana pulp (GBP) on theological behaviour and chemical characteristics of emulsions (mayonnaises) was investigated in this work. Five formulations were developed, using an experimental design for constrained surfaces and mixtures, with the following proportions (water/soybean oil/GBP): F1 (0.10/0.20/0.70), F2 (0.20/0.20/0.60), F3 (0.10/0.25/0.65), F4 (0.20/0.25/0.55) and F5 (0.15/0.225/0.625). Rheological properties of the emulsions were obtained with a rotational Haake Rheostress 600 rheometer and a cone and plate geometry sensor (60 mm diameter, 2' cone angle), with a gap distance of 1 mm. The samples presented high values for mineral salts and low calories. The emulsions showed pseudoplastic behaviour at 10 and 25 degrees C and theological data were well described by the Herschel-Bulkley model. Formulations with high GBP content (F1 and F3) presented higher yield stress and apparent viscosity values. The results obtained with the response surface methodology, which were adjusted by the quadratic model, showed that GBP had a significant influence on the increase of yield stress and apparent viscosity. The consistency coefficient increased with an increase in soybean oil concentration and water contributed to high values of flow behaviour index in all emulsions samples. (c) 2007 Swiss Society of Food Science and Technology. Published by Elsevier Ltd. All rights reserved.