Evaluation of banana (Musa spp.) cultivars for dietary fibre

Abstract

Banana is grown under a wide range of environment in the tropical and subtropical regions of the world. Since the plant as a whole is useful for its fruits, peel, fibre, rhizome, male bud and pseudostem, it is also called as ‘Kalpatharu’. After harvesting bunches, the biomass left out are reported to be rich source of dietary fibre. Nowadays, the development and use of functional ingredients is widely exploited in the food industry, principally those with high dietary fibre levels. Dietary fibres are plant derived complex carbohydrates, which have immense health beneficial effects. These plant parts, which are rich in dietary fibre could be used as a potential source of dietary fibre in food products. In this context, the present study was carried out in the Department of Post-Harvest Technology, College of Agriculture, Vellanikkara and Banana Research Station, Kannara, with the objective to evaluate the quantity and quality of dietary fibre from various parts of banana cultivars and to utilize the dietary fibre enriched powder for product development. The cultivars, belonging to different genomes (Grand Naine (AAA), Kunnan (AB), Nedunendran (AAB) and Pisang Lilin (AA)) were planted in the field of Banana Research Station, Kannara. The plant parts such as male bud, peel, inner core of pseudostem and rhizome were collected and estimation of biomass and dietary fibre yield were carried out. The rhizome of cultivar Kunnan recorded the highest biomass content (6955.56 g) and male bud of Pisang Lilin recorded the lowest (190.68 g). Among different cultivars, the Kunnan recorded the highest biomass content (3989.25 g), which was on par with the Grand Naine (3920.64 g) and Pisang Lilin recorded the lowest biomass content (1400.61 g). When plant parts are taken separately irrespective of the cultivars, the rhizome recorded the highest biomass content (5031.94 g) and male bud recorded the lowest (421.79 g). The dietary fibre content was recorded as highest in the rhizome of Pisang Lilin (72.10 %) and lowest in the inner core of pseudostem of Grand Naine (22.96 %). With respect to each cultivar, highest dietary fibre content was recorded in the rhizome of Pisang Lilin (72.10 %) and male buds of Kunnan (54.24 %), Nedunendran (42.43 %) and Grand Naine (38.82 %), followed by the rhizomes of Kunnan (50.83 %) and Grand Naine (37.19 %). These plant parts were powdered and the quality evaluation of dietary fibre for antioxidant activity, total phenols, lignin, cellulose, carbohydrate, swelling power and solubility was done. The male bud powder of Kunnan recorded the lowest phenol content (0.63 mg/g) and rhizome powder of Pisang Lilin recorded the highest phenol content (3.64 mg/g). The highest lignin content (17.05 %) and solubility (15.30 %) was recorded in the male bud powder of Kunnan. The cellulose content (22.50 %) as well as antioxidant activity (0.18 μg/ml) was recorded as highest in the rhizome powder of Grand Naine whereas, the carbohydrate (20.35 g/100g) content was highest in the male bud powder of Grand Naine. The swelling power was highest in the rhizome powder of Kunnan (5.03). As the male bud powder of Kunnan recorded the highest values for most of the quality attributes, it was selected for the product development. Thus, cookies were prepared by incorporating the male bud powder of Kunnan at different concentrations (10 %, 20 %, 30 %, 40 % and 50 %) to the banana flour. The cookies under control were prepared using 100 % banana flour. The cookies were evaluated for their biochemical and sensory attributes. The biochemical parameters such as protein, total minerals, calcium, potassium, dietary fibre and fat content increased with the level of incorporation of male bud powder of Kunnan and were highest for the cookies incorporated with 50 % Kunnan male bud powder. The carbohydrate, starch, total sugars and energy value decreased with the level of incorporation of Kunnan male bud powder, and were highest for the cookies under control. The sensory evaluation of the cookies was carried out using 9-point hedonic scale. The cookies incorporated with 10 % male bud powder of Kunnan adjudged as the best with respect to different sensory attributes analyzed, resulting in better overall acceptability. Hence, the cookies with 10 % incorporation of Kunnan bud powder was selected as the best treatment. The male bud powder of ‘Kunnan’ was proved to be the best among the different parts of cultivars studied, with respect to the quality attributes of dietary fibre such as phenol content, lignin content and solubility as well as for acceptability. Hence, there exist immense scope for Kunnan bud powder in the area of production of dietary fibre enriched products.