Foxtail millet, as a leading variety in arid and semi-arid areas of Asia and Africa, can provide broad potential benefits to human health. However, its digestion properties have not been reported. So in this study, the in vitro starch digestibilities and in vivo glycemic indices (GI) of foxtail millet and pure millet products were investigated. The results showed that starch digestibility of the foxtail millet flour is obviously lower than that of wheat flour. However, deproteinization and heating significantly increased its rapidly digestible starch and decreased its slowly digestible starch and resistant starch. The GIs of pure millet products were in the following order: millet porridge (93.6 ± 11.3) > millet steamed bread (89.6 ± 8.8) > No. 1 millet pancake (75.0% millet flour and 25.0% extrusion flour, 83.0 ± 9.6) > No. 2 millet pancake (without extrusion flour, 76.2 ± 10.7) > cooked millet (64.4 ± 8.5). They were significantly positively correlated with the rapidly digestible starch (r = 0.959), degree of gelatinization (r = 0.967) and estimated glycemic index (r = 0.988). Both in vitro and in vivo tests suggested that boiling, steaming and extrusion enhanced the formation of digestible starch and subsequently increased the GI values. Additionally, the No. 1 millet pancake and cooked millet had a relatively gentle stimulation on β-cell. Therefore, foxtail millet, especially the cooked millet, may serve as a potential source of nutraceutical and functional food that could delay the development of type 2 diabetes.
The research was conducted to assess the variability and relationship regarding physicochemical properties, antioxidant activity and bioactive compounds in edible and nonedible portions (peel, flesh and seed) of dragon fruit cultivars native to Bangladesh. The most popular and largely cultivated Bangladesh Agricultural Research Institute (BARI) released BARI Dragon Fruit-1 and Bangladesh Agricultural University (BAU) released BAU Dragon Fruit-1 cultivars were chosen in the study. The experiment was conducted in two factors completely randomized design where two cultivars and, three edible and nonedible portions were considered as treatments. The findings of the investigation revealed that there was a large discrepancy in the average weight in the selected cultivars where BAU Dragon Fruit-1 was found to be superior (347 g) to BARI Dragon Fruit-1 (284 g). These cultivars contained 31.86% to 35.44% peel, 59.74% to 65.08% flesh and 3.06% to 4.82% seed in their edible and non-edible portions. The BAU Dragon Fruit-1 provided a good recovery rate with the highest flesh to peel ratio (2.04:1). The highest amount of total soluble solids (10.20°Brix) was obtained in the flesh portion of BARI Dragon Fruit1. The utmost quantities of ascorbic acid were found in the seeds of each cultivar, ranging from 24.40 to 31.41 mg/100 g. The BARI Dragon Fruit-1 cultivar’s seed contained the highest tannin (444.64 mg TAE/100 g), whereas the flesh of the same cultivar had the lowest (335.04 mg TAE/100 g). In comparison, the phenolic content of BAU Dragon Fruit -1 cultivar's seed and flesh ranged from 162.86 to 163.13 mg GAE/100 g. The highest antioxidant activity (91.35%) was found in the seed portion of BARI Dragon Fruit-1. According to the findings, the edible and non-edible portions of Bangladesh's native dragon fruit cultivars have particular features, which will help in diverse food and pharmaceuticals product formulation and development.
Jellies are usually preserved by artificial preservatives where they have harmful side effects and health hazards especially to infants. Honey and fresh lemon extract juice is a natural preservative and is considered a good substitute for artificial preservative. Due to increasing level of demand regarding health concern issue safe food, an attempt has undertaken to formulate the artificial preservative free guava–pineapple jelly and their marketability, physicochemical, bioactive compounds, microbial and antioxidant properties analysis during storage. In this study, the jelly was formulated using artificial preservative potassium metabisulphite (KMS) (T1), natural preservative honey and fresh lemon extract juice (T2 and T3), without artificial and natural preservative (T4) using different proportion of guava–pineapple extracted juice. Results of different treated jelly showed that T2 and T3 jelly was nutritionally superior. Bioactive compounds and antioxidant properties was highly present in T2 and T3 jelly. The brightest color (L* and C*) and highest hue angle (H*) value was noted in honey and fresh lemon extract juice treated jelly T2 and T3 upto 8 months of storage but after 9 months, darkest color was noted gradually. The consumer acceptance was extended to honey and lemon extract juice treated jelly (T2 and T3) for their impressive color and flavor. High incidence of microbial load was recorded in preservative free (both natural and artificial) jelly (T4). Low incidence of microbial load obtained from this study gives an indication that T2 and T3 jelly is microbiologically safe as natural jelly. Shelf life of natural preservative treated jelly (T2 and T3) could be extended upto 8 months and artificial preservative treated jelly could be upto 9 months (T1) at ambient condition without any quality deterioration. Overall, honey and fresh lemon extract juice are valuable source of natural preservative for formulation of fruit jelly. The processors could process and preserve the fruit jelly with decent aroma by applying this technology as an alternative to artificial food additives.