Characterization and functionality of fibre-rich pomaces from the tropical fruit pulp industry

Abstract

PurposeThe purpose of this paper is to evaluate the chemical and functional composition of acerola, guava and cashew freeze-dried pomaces.Design/methodology/approachFruit pomaces were obtained from the pulp juice industrial sector and submitted to freeze-drying. Samples were analysed for composition (macronutrients, micronutrients, moisture and ash), technological attributes (morphological, hygroscopicity, retention of oil and water and solubility), bioactive compounds (total phenolics, flavonoids, proanthocyanins, anthocyanins, carotenoids and ascorbic acid), antioxidant and antimicrobial properties. Total phenolics, brown pigments and antioxidant activity of thermally treated samples were evaluated. Results were presented as mean and standard deviation, and submitted to Shapiro–Wilk normality test, and ANOVA statistical significance follows by Tukey’s post hoc test (p<0.05). Also, Pearson correlation coefficients were used to test the relationship between selected parameters.FindingsGuava pomace had the highest insoluble fibre (40.6 per cent), protein (13.8 per cent) and lipid (9.3 per cent) contents and acerola higher soluble fibre (14.2 per cent) and water and oil holding capacity (12 and 5.4 g/g, respectively). Cashew pomace had higher solubility (45.3 per cent) and hygroscopicity (11.2 per cent). Acerola pomace had the highest phenolic content (5,331.7 mg AGE/100 g), DPPH and oxygen radical absorbance capacity antioxidant activity (63.3 and 756.6 µmol TE/g). Despite of that none of extracts showed antibacterial activity. All pomaces presented good antioxidant activity retention after thermal treatments (> 70 per cent), which might be correlated to thermally induced brown pigments.Originality/valueThis investigation was motivated by the large amounts of pomaces produced by the fruit pulp and juice processing industries, which represents a waste of residual phytochemicals and cause potential environmental problems. Overall, it was demonstrated that freeze-dried acerola, guava and cashew pomaces are promising ingredients for multiple food applications.