In vitro examination of starch digestibility of Saba banana [Musa 'saba'(Musa acuminata × Musa balbisiana)]: impact of maturity and physical properties of digesta

Solid-state fermentation of Saba banana peel for pigment production by Monascus purpureus

Eco-friendly natural pigment demand has ever-increasing popularity due to health and environmental concerns. In this context, the aim of this study was to evaluate the feasibility use of Saba banana peel as low-cost fermentable substrate for the production of pigments, xylanase and cellulase enzymes by Monascus purpureus. Among the strains tested, M. purpureus TISTR 3385 produced pigments better and had higher enzyme activities. Under the optimal pigment-producing conditions at the initial moisture content of 40% and initial pH of 6.0, the pigments comprising yellow, orange, and red produced by the fungi were achieved in the range of 0.40-0.93 UA/g/day. The maximum xylanase and cellulase activities of 8.92 ± 0.46 U/g and 4.72 ± 0.04 U/g were also obtained, respectively. More importantly, solid-state fermentation of non-sterile peel could be achieved without sacrificing the production of the pigments and both enzymes. These indicated the potential use of the peel as fermentable feedstock for pigment production by the fungi and an environmental-friendly approach for sustainable waste management and industrial pigment and enzyme application.

Nutraceutical Difference between Two Popular Thai Namwa Cultivars Used for Sun Dried Banana Products

Musa (ABB group) “Kluai Namwa” bananas (Musa sp.) are widely grown throughout Thailand. Mali Ong is the most popular Kluai Namwa variety used as raw material for sun-dried banana production, especially in the Bangkratum District, Phitsanulok, Thailand. The sun-dried banana product made from Nanwa Mali Ong is well recognized as the best dried banana product of the country, with optimal taste compared to one made from other Kluai Namwa varieties. However, the production of Mali Ong has fluctuated substantially in recent years, leading to shortages. Consequently, farmers have turned to using other Kluai Namwa varieties including Nuanchan. This study investigated the nutraceutical contents of two popular Namwa varieties, Mali Ong and Nuanchan, at different ripening stages. Nutraceuticals in the dried banana products made from these two Kluai Namwa varieties and four commercial dried banana products were compared. Results indicated that the content of moisture, total sugar, and total soluble solids (TSS) (°Brix) increased, while total solids and texture values decreased during the ripening stage for both Kluai Namwa varieties. Rutin was the major flavonoid found in both Namwa Mali Ong and Nuanchan varieties ranging 136.00−204.89 mg/kg and 129.15−260.38 mg/kg, respectively. Rutin, naringenin, quercetin and catechin were abundant in both Namwa varieties. All flavonoids increased with ripening except for rutin, gallocatechin and gallocatechin gallate. There were no significant differences (p < 0.05) in flavonoid contents between both varieties. Tannic acid, ellagic acid, gallic acid, chlorogenic acid and ferulic acid were the main phenolic acids found in Mali Ong and Nuanchan varieties, ranging from 274.61−339.56 mg/kg and 293.13−372.66 mg/kg, respectively. Phenolic contents of both varieties decreased, increased and then decreased again during the development stage. Dopamine contents increased from 79.26 to 111.77 mg/kg and 60.38 to 125.07 mg/kg for Mali Ong and Nuanchan, respectively, but the amounts were not significantly different (p < 0.5) between the two Namwa varieties at each ripening stage. Inulin as fructooligosaccharide (FOS) increased with ripening steps. Production stages of sun-dried banana products showed no statistically significant differences (p < 0.05) between the two Namwa varieties. Therefore, when one variety is scarce, the other could be used as a replacement in terms of total flavonoids, phenolic acid, dopamine and FOS. In both Namwa varieties, sugar contents decreased after the drying process. Sugar contents of the dried products were 48.47 and 47.21 g/100 g. The drying process caused a reduction in total flavonoid contents and phenolic acid at 63−66% and 64−70%, respectively. No significant differences (p < 0.05) were found for total flavonoid and phenolic contents between the dried banana products made from the two Namwa varieties (178.21 vs. 182.53 mg/kg and 96.06 vs. 102.19 mg/kg, respectively). Products made from Nuanchan varieties (24.52 mg/kg) contained significantly higher dopamine than that from Mali Ong (38.52 mg/kg). The data also suggest that the banana maturity stage for production of the sun dried products was also optimum in terms of high nutraceutical level.

Changes in bioactive compounds and antioxidant activity of plant-based foods by gastrointestinal digestion: a review

Phenolic compounds, omnipresent in plants, are a crucial part of the human diet and are of considerable interest due to their antioxidant properties and other potential beneficial health effects, for instance, antidiabetic, antihypertensive, anti-inflammatory, and anticancer properties. The consumption of a variety of plant-based foods containing various phenolic compounds has increased due to published scientific verification of several health benefits. The release of phenolic compounds and change in their bioactivities examined through in vitro simulated gastrointestinal digestion could provide information on the biological potency of bioactive components, which will allow us to elucidate their metabolic pathways and bioactivities at target sites. This review reports on the recent research results focused on changes during the gastro and/or intestinal phase. The effect of digestive enzymes and digestive pH conditions during simulated digestion accounted for the variations in bioaccessibility and bioavailability of phenolic antioxidants as well as the corresponding antioxidant activities were also summarized and presented in the review.

Bio-properties of Saba banana (Musa 'saba', ABB Group): Influence of maturity and changes during simulated in vitro gastrointestinal digestion

Saba banana, a popular fruit crop grown in Southeast Asia, is an economical source of a variety of beneficial agents. This study examined the variations in total phenolic, flavonoid, and antioxidant activities of five maturity stages of Saba banana, and their changes during simulated in vitro gastrointestinal digestion as affected by varying structural compositions. Antioxidant activities were evaluated using ferric reducing antioxidant power (FRAP), metal ion chelating (MIC) activity, and 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays. Results of DPPH and ABTS were compared in terms of TEAC (Trolox Equivalent Antioxidant Capacity) and VCEAC (Vitamin C Equivalent Antioxidant Capacity) values. Bio-properties were found to be highest in mature green stage with values slightly decreased as ripening proceeded. Simulated digestion showed a continuous increase in total phenolic with comparatively faster release in structure-less state (slurry) than samples with intact structure (cut). The trend of antioxidant activities was increased in the gastric phase and then decreased at the onset of intestinal phase, except for MIC which showed a reverse effect. Our study indicated that the bio-properties of Saba banana were affected by maturity and modifications in its physical structure and composition could influence the release behaviors of food components during simulated digestion.