One way to valorize “Saba” banana peel waste is to extract high-value compounds, such as pectin, and use it for food applications. In this study, the parameters for the microwave-assisted extraction of pectin were screened and optimized using Response Surface Methodology. The pectin was purified and then subjected to characterization. Results showed that the optimum extraction conditions were 195°C, 8% solid-liquid ratio, and pH 3 hydrochloric acid (HCl), with predicted and actual yields of 12.8% and 14.2%, respectively. The subsequent purification method increased the purity of pectin by 300%. The pectin was found to be low-methoxy in nature and had an average particle size of 300 nm. The pectin application in whey protein isolate resulted in a shear-thinning fluid, with an improved viscosity compared to a control. When applied to a commercial orange juice, the in vitro digestion study showed that the fluid’s viscosity was higher before and during the gastric and intestinal digestion at the low physiological shear rate.

The effects of maturity (green-unripe, red-ripe, and purple-fully ripe) and heat treatment (blanching at 90±5°C for 2 mins and steaming at 105±5°C for 5 mins) on the antioxidant content and activity of Philippine bignay (Antidesma bunius (Linn.) Spreng cv. ‘common’) flesh and seeds were investigated. The total phenolic content (TPC), total flavonoid content (TFC) and total anthocyanin content (TAC) were determined using the Folin-Ciocalteau assay, aluminum chloride assay, and pH differential technique, respectively, and the antioxidant activity was determined using DPPH, ABTS, and FRAP assays. Results showed that the antioxidant content and activity of bignay increased with maturity. Fully ripe flesh and seeds were found to have the highest antioxidant content and activity regardless of the heat treatment applied. The TPC (8.06±0.15 mg gallic acid equivalents (GAE)/g), TFC (8.10±0.06 mg quercetin equivalents (QE)/g), TAC (4.07±0.03 mg cyanidin-3-glucoside equivalents (CGE)/L extract), and antioxidant activity (ABTS 10.37±0.04 , DPPH 9.60±0.10, FRAP 24.37±0.53 Trolox equivalents (TE)/g) of fully ripe seeds were superior when blanched. On the other hand, the TPC (40.73±0.04 mg GAE/g), TFC (31.54±0.15 mg QE/g), TAC (20.93±0.12 mg CGE/L extract), of fully ripe flesh were superior when not heat-treated while its antioxidant activity (ABTS 34.19±0.19, DPPH 14.01±0.02, FRAP 87.78±1.22 (TE)/g) was highest when blanched but did not vary significantly compared to unheated samples. This study suggested that bignay ‘common’ variety was a good source of antioxidants particularly the flesh at fully ripe stage. Blanching had shown to enhance its antioxidant activities.

‘Saba’ banana peel contains significant amounts of pectin but with very limited commercial use. To increase its value, the present study investigated the effect of ‘saba’ peel pectin (SPP) on biomarkers of obesity and associated blood lipid disorders in vivo and identified its potential mechanism via in vitro lipid lowering assays. ICR male mice were induced with obesity and hypercholesterolemia using 45% high fat diet (HFD) for three weeks. The mice were then randomly allocated to four groups fed various diets ad libitum for nine weeks as follows: (1) normal diet (ND), (2) high-fat diet (HFD), (3) HFD with 10% w/w commercial citrus pectin (HFD-CCP), and (4) HFD with 10% w/w SPP (HFD-SPP). For the in vitro study, lipid lowering assays were carried out using published protocols with some modifications. Results showed that the mean endline body weight of HFD-CCP and HFD-SPP were significantly lower than HFD group despite having comparable feed intake. The pectin-supplemented groups also had lower blood total cholesterol than HFD group. Necropsy results showed no significant treatment-related difference in the relative organ weights, except for the liver of HFD group being pale, enlarged, and heavier than the other mice groups. This is consistent with the microscopic observations of liver sections from HFD-CCP and HFD-SPP which had occasional fat deposits only whereas HFD group showed mild necrosis and fat infiltration. In terms of body fat, the adiposity index was significantly lower among HFD-SPP and HFD-CCP than the HFD group, with both pectin-supplemented groups showing lesser extent of increase in adipocyte diameter. Meanwhile, HFD-CCP and HFD-SPP groups were significantly comparable in terms of body weight, blood lipids, organ and adipose tissue weights, adiposity index, and liver morphology. In vitro assays revealed that SPP had significantly higher cholesterol and bile acid binding capacities at 60 μg/mL and 20 μg/mL, respectively than CCP and bile acid-binding drug, cholestyramine. These showed that SPP supplementation improves biomarkers of obesity and associated blood lipid disorders at par with commercially-available citrus pectin possibly via cholesterol and bile acid binding pathways, suggesting that SPP may be a potential functional ingredient with anti-obesity and anti-hypercholesterolemic properties.

This study aimed to determine the influence of maturity stages and processing methods (blanching and steaming) on the antioxidant profile and in vitro antioxidant activities of bignay (Antidesma bunius (Linn.) Spreng var. Kalabaw) flesh and seeds. Bignay fruits of three maturities (unripe, half ripe, and fully ripe) were collected from Laguna, Philippines. Each maturity stage was subdivided into three lots. One lot underwent blanching at 90 ± 5°C for 2 minutes, and another underwent steaming at 105 ± 5°C for 5 minutes while the last did not undergo treatment. Seeds of the samples were then separated from the flesh. Both seeds and flesh were freeze-dried, extracted, and analyzed for antioxidant contents (total phenolic content, total flavonoid content, and total anthocyanin content) and antioxidant activity by DPPH, ABTS, and FRAP assays. Results show that both the maturity and processing methods significantly affect the antioxidant content and activity of the samples. Moreover, except for the FRAP assay done on flesh samples, all assays showed that there is significant interaction between the effect of maturity and processing method on the antioxidant contents and activity of bignay flesh and seeds. Results also show that fully ripe flesh and seeds yielded greater antioxidant content and antioxidant activity than their half-ripe and unripe counterparts; whereas, blanched flesh and seeds generally had higher antioxidant activities than their unprocessed and steamed counterparts.

No abstract