Comparative assessment of different drying techniques on physicochemical, proximate, antioxidant and sensory properties of Bilimbi Fruit (Averrhoa Bilimbi L.)

Abstract

Bilimbi (Averrhoa bilimbi L.) is one of the underutilized fruits found in tropical countries. Given its high perishability, drying is one of the best preservation methods for extending its shelf-life, with a focus on its large export market potential. However, compared to fresh, drying may significantly affect organoleptic and nutritional qualities of foods. Therefore, the present study aimed to evaluate and compare the physicochemical, proximate, antioxidant and sensory properties of bilimbi fruit prepared from different drying techniques. Fresh bilimbi slices (2 mm in thickness) were pre-treated with 1% salt solution w/v for 5 min and dried using different drying techniques such as sun drying (direct sunlight, 3 hrs), dehydrator drying (55 °C, 1 hr), electric oven drying (100 °C, 40 min) and microwave oven drying (low heat, 35 min). Standard methods were used to analyze the physicochemical, nutritional, and antioxidant properties of dried fruits while 30 semi-trained panelists were used to conduct the sensory analysis with a 7-point hedonic scale. Results showed that dehydrated sample had the highest sensory attributes, rehydration ratio (3.97 ± 0.02), whiteness index (435.87 ± 56.5), yellowness index (57.32 ± 4.52), crude protein (5.50 ± 0.15%), crude fat (3.64 ± 0.01 %), crude fiber (8.939 ± 1.26 %) and the lowest water activity (0.48 ± 0.002). Microwave oven-dried samples exhibited the highest amount of ash (17.1 ± 3.14%) and total polyphenol (71.96 ± 1.27 mg GAE/g) with the least moisture content (5.17±0.08%). However, the highest DPPH radical scavenging activity (10.04 ± 0.003 μg TE /g) was reported in sun-dried bilimbi sample. Overall, it can be concluded that dehydrator drying was the best drying method to preserve the sensory and nutritional qualities of bilimbi fruits.