Physicochemical and Processing Qualities of Guava Varieties in Kenya

Abstract

ABSTRACT Despite Kenya’s favorable climate for both exotic and indigenous commercial guava production, neglect has limited research on the fruits’ physicochemical and processing qualities. The white-fleshed, red/pink-fleshed guava, and, to a lesser extent, strawberry guavas that grow in different agroecological zones are the most common Kenyan varieties. The purpose of this study was to determine the physicochemical properties and processing qualities of the common Kenyan guava fruits. A completely randomized study design was used to profile the fruits' physicochemical composition and processing qualities. Approximately 1000kg of the red and white-fleshed guava fruits and 150 kg of strawberry guavas were procured in duplicates from randomly selected trees in farms within Taita Taveta and Kitui counties. These were pooled into respective varieties and subjected to triplicate batches for the analysis of physicochemical and processing qualities. The fruits had distinct flesh colors and sizes that varied significantly (p<0.05), with shapes ranging from oval to round to pear-shaped. The chemical composition of the fruits varied significantly (p<0.05), with a PCA biplot explaining approximately 58% of the variability due to intra (61%) and inter (39%) varietal differences. The strawberry guava’s vitamin C levels were significantly (p=0.0001) lower than the red and white guavas’, at 164.11±11.85, 1365.15± 50.56 and 1665.56±126.50 mg100−1g, respectively. The white-fleshed guavas, on the other hand, were low in β-carotenes (0.04±0.06 mg100−1g) in comparison to the red-fleshed (1.98±0.62mg100−1g) and strawberry guava (1.55 ± 0.30mg100−1g). The strawberry guavas had significantly (p<0.05) higher mineral and total flavonoids contents whereas the total phenolics (1649.14±329.70mgGAE100−1g) and antioxidant activities (1989.14±383.47µMTE100−1g) were significantly (p=0.048) higher in the red-fleshed guava. While strawberry production would be a processing constraint, the red-fleshed guavas had significantly (p<0.05) higher beta-carotene, phytochemicals, and minerals than the white, and therefore best suited for processing.