Enhancing quality and stability of guava nectar using tomato seed protein isolate and hydrolysate: physico-chemical, bioactive, rheological, and sensory assessment

The objective of the research was to enhance the quality and stability of guava nectar by adding tomato seed protein isolate (TSPI) and hydrolysate (TSPH) at different levels (1, 1.5 and 2%). The physico-chemical, sugar, protein profile, rheological, Fourier Transform Infrared Spectroscopy (FTIR) and sensory parameters of the protein enriched guava nectar were assessed. The findings showed that with the enrichment of TSPI and TSPH, the crude protein content (0.10 to 1.72%), total polyphenols (146.62 to 156.08 mg GAE/100mL), flavonoids (27.42 to 30.19 mg RE/100mL), and antioxidant activity (34.34 to 37.15%), of the guava nectar enhanced in comparison to control guava nectar. The rheological properties such as viscosity curve and frequency sweep were altered by the enrichment of TSPI and TSPH in guava nectar. According to the sensory study; colour, flavour, mouth feel, and overall acceptability decreased with increasing enrichment levels of protein isolate and hydrolysate. The sensory characteristics of guava nectar enriched with 1% TSPI and TSPH were comparable to that of control guava nectar. Thus, this work offers insightful information about how TSPI and TSPH may be used to enrich the protein content, bioactive properties and technological quality of guava nectar.

Graphical abstract