No abstract

Melon Manis Terengganu (MMT) is comprised of 28 - 30% peel which is a by-product of food processing. The peel is a source of dietary fibre which has a potential role in glycaemic response. The present work thus aimed to develop formulated MMT peel powder, and examine its organoleptic properties, in vitro hypoglycaemic effect, and starch digestibility. The MMT peel powder was formulated as Formulations 0, 1, 2, and 3 with different sweetener ratios (0, 40, 50, and 60%), and subjected to sensory evaluations. Tukey’s post-hoc test was used to evaluate significant differences between mean values following one-way analysis of variance (ANOVA). Meanwhile, the Friedman test followed by Wilcoxon signed ranks test were performed for sensory evaluation analysis. Results demonstrated that the most acceptable formulation for consumption assessed using sensory evaluation was Formulation 3; its total, digestible, and resistant starch content were the lowest among all the formulations. The same went to the hydrolysis index and estimated glycaemic index. However, Formulation 3 was the least effective in reducing glycaemic response due to the weakest in vitro hypoglycaemic activity. On the other hand, the mentioned attributes previously were observed in Formulation 0 in an opposite manner. In summary, these findings suggested that formulated MMT peel powder had the potential to be used in blood glucose control.

Background Melon Manis Terengganu (MMT) peel has a high dietary fiber content, but there is no data examining its health benefits in adults at risk of type 2 diabetes. The objective of the study was to evaluate whether consumption of MMT peel powder improves glycemic response, satiety, and food intake in adults at risk of type 2 diabetes. Methods An open-label, randomized, placebo-controlled, crossover design trial was conducted among adults (n = 30, ages 18–59 y) at risk of type 2 diabetes. They consumed Formulation 3 (formulated MMT peel powder) [A] and control (glucose) [B] with study breakfast based on randomly assigned treatment sequences (AB, BA) established by Research Randomizer (www.randomizer.org). Capillary blood glucose and perceived satiety were determined at baseline (0 min), 30, 60, 90 and 120 min, followed by a post-intervention food intake measurement. Results The repeated measures analysis of variance (ANOVA) revealed significant time (F = 84.37, p <  0.001, ηp2 = 0.744), condition (F = 22.89, p <  0.001, ηp2 = 0.441), and time*condition effects (F = 24.40, p <  0.001, ηp2 = 0.457) in blood glucose levels. Respondents (n = 30) who consumed Formulation 3 also had a significantly lower blood glucose 2-hour incremental area under the curve (iAUC) of 134.65 ± 44.51 mmol/L*min and maximum concentration (CMax) of 7.20 (7.10, 8.20) mmol/L with relative reduction of 26.8 and 13.3% respectively, when compared with control (p <  0.001). Besides, significantly greater perceived satiety, lower energy and fat intake as well as higher dietary fiber intake were also observed in the intervention group compared with the placebo group (p <  0.05). There were no marked side effects associated with the ingestion of the test products. Conclusions Short-term consumption of formulated MMT peel powder may improve glycemic response, increase perceived satiety and reduce food intake in adults at risk of type 2 diabetes with the potential to be utilized as a functional beverage. Medium-to long-term clinical trial is warranted to determine whether taking this formulated MMT peel powder on a daily basis has an influence on health outcomes. Trial registration ClinicalTrials.gov Identifier: NCT05298111. Registered 28/03/2022.

Melon Manis Terengganu (MMT) also known as Cucumis melo var. Inodorus cv. Manis Terengganu 1 originates from Terengganu, Malaysia, is composed of 28–30% inedible peels and discarded as waste. Hence, this study aimed to quantify the polyphenol and flavonoid contents, identify polyphenolic compounds and evaluate the antioxidant activity of freezedried Melon Manis Terengganu (MMT) peel aqueous extract. The total phenolic and flavonoid contents were determinedspectrophotometrically by gallic acid and quercetin standard curves, respectively. Whereas, antioxidant activity was explored by using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2-azino-bis (3 ethylben-zothiazoline-6-sulfonic acid) diammonium salt (ABTS) assay. Next, liquid chromatography-mass spectrometry (LC-MS) was applied for phenolic compounds identification. Results reported that the total phenolic content was 12.35 (0.59) μg GAE/mg while total flavonoid content was 2.01 (0.70) μg QE/mg. The IC50 of DPPH and ABTS assay were 27.74 (1.59) mg/mL and 4.87 (0.06) mg/mL, respectively. LC-MS results revealed the presence of polyphenolic compounds, such as kaempferol 3-(6'’-sinapylglucosyl)-(1->2)-galactoside), isoorientin 7-O-(6'”-O-(E)-feruloyl)glucoside and isoscoparin 2'’-(6-(E)-ferulylglucoside) in the sample extract. In summary, these findings served as preliminary data for further exploration on the potential application of freezedried MMT peel aqueous extract in the food and nutraceutical industry.