Effect of pulping methods on the physicochemical properties of the Kenyan red and white‐fleshed guava pulp

Abstract

AbstractBackgroundAlthough fruit pulping is a highly effective global practice for ensuring a steady supply of fruit for processing during the off‐season, industrial pulping of Kenyan guava cultivars is lacking, contributing to their annual losses. The present study compared the yield characteristics, physicochemical profile, and nutrient retention of pulp extracted from white and red‐fleshed Kenyan guavas using cold and hot extraction methods.ResultsThe pulp yield was highest in the red guava with the pulp to by‐product ratio being significantly (p < 0.05) higher at 2.58, 2.97, and 3.30 for cold, hot water, and steam‐blanched compared to 1.66, 1.95, and 2.03 for the white guava respectively. Although hot extraction methods resulted in significantly (p < 0.0001) higher yields (67%–77%) compared to the cold (62%–73%), the heat‐labile nutrients were affected with as much as 60% and 64% of the white and the red guava's vitamin C being lost. The steam blanched pulps exhibited significantly (p < 0.0001) high overall color changes (∆E) ranging from 22–30 in the pasteurized white guava pulp compared to the red's (−0.24–6). The cold extraction method resulted in better retention of β‐carotene (1.9 ± 0.4 mg), zinc (5.6 ± 2.1 mg), iron (20.1 ± 8.6 mg), flavonoids (241.3 ± 56mgCE), phenolics (1548.7 ± 25.8mgGAE) and antioxidant activities (1998.6 ± 333μMTE) per 100 g in the red guava pulp.ConclusionCompared to the white cold‐extracted pulp, the red guava pulp was more suitable for further processing due to its high nutrient retention, high pulp to by‐products ratio, and textural properties therefore recommended for the adoption of processing the Kenyan guava cultivars.