Influence of Clitoria ternatea Flower Extract on the In Vitro Enzymatic Digestibility of Starch and Its Application in Bread

Phytochemical-Rich Colored Noodles Fortified with an Aqueous Extract of Clitoria ternatea Flowers

Clitoria ternatea (CT) flowers are rich in phytochemicals. An innovative approach was taken to utilize CT flower extract (CTFE) as a functional ingredient with natural pigment by incorporating it into noodles. The aim of this study was to examine the effect of the CTFE amount (0-30%) on the color, texture, phytochemicals, and sensory quality of both dried and cooked noodles. Dried noodles with 30% CTFE had the highest total anthocyanins (9.48 μg/g), polyphenols (612 μg/g), DPPH radical scavenging capacity (165 μg TE/g), and reducing power (2203 μg TE/g). Cooking resulted in a significant decrease in the anthocyanin levels and blue color, while also increasing the greenness of the noodle. Both dried and cooked noodles with 20-30% CTFE showed a significantly higher color preference compared to the control sample. Despite a significant reduction in the cutting force, tensile strength, and extensibility of cooked noodles with 20-30% CTFE, the sensory attributes such as flavor, texture, and overall preferences were similar to those of noodles with 0-30% CTFE. Blue noodles with high phytochemicals, antioxidant activities, and desirable sensory qualities can be produced by the incorporation of 20-30% CTFE.

Effect of Euryale ferox seed shell extract addition on the in vitro starch digestibility and predicted glycemic index of wheat-based bread

The inhibitory effects of Euryale ferox seed shell extract (EFSSE) on the activity of α-amylase and α-glucosidase were studied. EFSSE (0.25 % to 2 %) was used to fortify bread and analyzed the in vitro starch digestibility (IVSD) digestion kinetics, and the predicted glycemic index (pGI) was estimated. The swarm intelligence supervised neural network (SISNN) technique was applied for the predictive simulation of digestion kinetics and pGI. Principal component analysis (PCA) with proportional odds modeling (POM) was used to find the most sensitive component based on the sensory attributes of bread. The inhibitory effect of EFSSE on α-amylase and α-glucosidase in terms of IC₅₀ was 62.95 and 52.06 μg/mL, respectively. Fortification of bread with EFSSE could affect loaf volume, hardness, and color. Euryale ferox seed shell extract could decreased the rate of hydrolysis of bread. EFSSE (2 %) had a strong inhibitory impact, as evidenced by the drop in glycemic index from 94.61 to 61.66. SISNN-based kinetics was much better as compared to mathematical modeling-based digestion kinetics. Findings of the present study have shown that EFSSE could be employed as an additive to produce lower glycemic index functional bread.

Organoleptic, hypoglycaemic, and in vitro starch digestion effects of formulated Melon Manis Terengganu peel powder

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.

Substituting Whole Wheat Flour with Pigeon Pea (Cajanus cajan) Flour in Chapati: Effect on Nutritional Characteristics, Color Profiles, and In Vitro Starch and Protein Digestion

Pigeon pea (Cajanus cajan (L.) Millsp.), a potential legume as an economical source of protein, is commonly cultivated in tropical and subtropical regions of the world. Therefore, pigeon pea may be potentially used as a substitute to improve the nutritional profile of foods. In the present study, the effect of substitution of whole wheat flour (WWF) with 20% and 40% pigeon pea flour (PPF) on the nutritional properties, color profiles, and starch and protein digestibility of chapati was investigated. The results showed that PPF had higher protein content but less carbohydrate than WWF. The protein content of chapati substituted with 20% and 40% PPF increased by 1.18 and 1.34 times, respectively, compared to WWF chapati, along with a marked decrease in carbohydrate content. Analyses further revealed an increase in the lightness and yellowness and a decrease in the redness of the chapati. Furthermore, glucose release from chapati with 20% and 40% PPF under simulated digestion was attenuated, corresponding to decreased hydrolysis and a predicted glycemic index. In the 40% PPF chapati, a significant reduction in slowly digestible starch (SDS) with increased resistant starch (RS) proportions was achieved without altering the effect on rapidly digestible starch (RDS). In addition, the level of amino-group residues was markedly elevated in 20% and 40% PPF substituted chapati compared to WWF chapati. These findings suggest that PPF can serve as a promising plant-based alternative ingredient to improve the nutrient value of chapati by reducing starch and increasing protein digestibility.

Antioxidant, cytotoxic, and antibacterial activities of Clitoria ternatea flower extracts and anthocyanin-rich fraction

Clitoria ternatea flower is a traditional medicinal herb that has been used as a natural food colourant. As there are limited studies on investigating the bioactivities of the anthocyanin-rich fraction of Clitoria ternatea flower, this study aimed to determine an efficient column chromatography method to obtain the anthocyanin-rich fraction from this flower and characterise its composition, antioxidant, antibacterial, and cytotoxic activities. Amberlite XAD-16 column chromatography was more efficient in enriching the total anthocyanin content (TAC) of the fraction with the highest TAC to total phenolic content (TPC) ratio of 1:6 than that using C18-OPN. A total of 11 ternatin anthocyanins were characterised in the anthocyanin-rich fraction by LC–MS analysis. The antioxidant activity of the anthocyanin-rich fraction was more potent in the chemical-based assay with an IC₅₀ value of 0.86 ± 0.07 mg/mL using 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay than cellular antioxidant assay using RAW 264.7 macrophages. In vitro cytotoxicity assay using human embryonic kidney HEK-293 cell line showed the anthocyanin-rich fraction to be more toxic than the crude extracts. The anthocyanin-rich fraction had more potent antibacterial activity than the crude extracts against Bacillus cereus, Bacillus subtilis, and Escherichia coli. The anthocyanin-rich fraction of C. ternatea has the potential to be used and developed as a functional food ingredient or nutraceutical agent.

Acute effect of Melon Manis Terengganu peel powder on glycemic response, perceived satiety, and food intake: a randomized, placebo-controlled crossover trial in adults at risk of type 2 diabetes

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, η_p² = 0.744), condition (F = 22.89, p <  0.001, η_p² = 0.441), and time*condition effects (F = 24.40, p <  0.001, η_p² = 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.

Investigating the Impact of Dragon Fruit Peel Waste on Starch Digestibility, Pasting, and Thermal Properties of Flours Used in Asia

As a by-product of dragon fruit consumption, dragon fruit peel (DFP) was developed into powder as a natural ingredient. Nevertheless, the effect of DFP on the physicochemical properties of flours used in Asian food processing and cooking remains unknown. In this study, starch digestibility, thermal, pasting, and physicochemical properties of DFP and flours (potato, rice, glutinous rice, and wheat) were characterized. It was found that DFP contained 65.2% dietary fiber together with phenolic compounds, betacyanins, and antioxidant activity. The results demonstrated that DFP (from 125 to 500 mg) reduced starch digestibility of flours, rapidly digestible starch, and slowly digestible starch, along with an increased proportion of undigested starch. A marked increase in phenolic compounds, betacyanins, and antioxidant activity occurred when DFP and flour were incubated for 180 min under simulated gastrointestinal digestion. The results indicate that bioactive compounds in DFP were highly bioaccessible and remained intact after digestion. Moreover, DFP exerted a significantly lower gelatinization enthalpy of flours with increasing peak viscosity and setback with decreasing pasting temperature. FTIR confirmed the decreased ratio at 1047/1022 cm−1, indicating the disruption of short-range orders of starch and DFP. These findings would expand the scope of DFP food applications and provide a knowledge basis for developing DFP flour-based products.

In Vitro Inhibitory Effects of Viburnum opulus Bark and Flower Extracts on Digestion of Potato Starch and Carbohydrate Hydrolases Activity

One of the effective treatments for diabetes is to reduce and delay the absorption of glucose by inhibition of α-amylase and α-glucosidase in the digestive tract. Currently, there is a great interest in natural inhibitors from various part of plants. In the present study, the phenolic compounds composition of V. opulus bark and flower, and their inhibitory effects on in vitro potato starch digestion as well as on α-amylase and α-glucosidase, have been studied. Bark and flower phenolic extracts reduced the amount of glucose released from potato starch during tree-stage simulated digestion, with IC50 value equal to 87.77 µg/mL and 148.87 µg/mL, respectively. Phenolic bark extract showed 34.9% and 38.4% more potent inhibitory activity against α-amylase and α-glucosidase, respectively, but the activity of plant extracts was lower than that of acarbose. Chlorogenic acid (27.26% of total phenolics) and (+)-catechin (30.48% of total phenolics) were the most prominent phenolics in the flower and bark extracts, respectively. Procyanidins may be responsible for the strongest V. opulus bark inhibitory activity against α-amylase, while (+)-catechin relative to α-glucosidase. This preliminary study provides the basis of further examination of the suitability of V. opulus bark compounds as components of nutraceuticals and functional foods with antidiabetic activity.

Multivariate Analysis of Butterfly Pea (Clitoria ternatea L.) Genotypes With Potentially Healthy Nutraceuticals and Uses

Butterfly pea (Clitoria ternatea L.) is a legume used as tea, forage, ornamental, salad, and medicinal plant. The flowers range from white to dark purple with little known about the variation for seed and flower color in the United States Department of Agriculture, Agricultural Research Service, Plant Genetic Resources Conservation Unit germplasm collection. Therefore, 26 butterfly pea accessions were analyzed using a principal component analysis (PCA) and average linkage cluster analysis (ALCA). These butterfly pea genotypes ranged from 56% to 99% for viabilities, 2.57 to 5.88 g for 100 seed weight, 34.07 to 226.26 g for total seed weight, and 1,326 to 3,874 for total seed numbers. PCA accounted for 40%, 57%, 70%, 79%, and 86% of the variation using principal components (PCs) 1 through 5, respectively. PC1 was most correlated with 100 and total seed weight, while PC2 correlated with blue, white, and purple flowers. PC3 correlated mostly with germination, purple flowers, and total seed weight. PCs 4 and 5 primarily correlated with blue and purple flowers, respectively. Several significant correlations were also observed. ALCA grouped the 26 butterfly pea genotypes into four distinct seed number-producing clusters. Clusters 1 to 4 represent the lowest to highest seed numbers produced by the butterfly pea genotypes. Several potential health benefits from butterfly pea flowers, leaves, seeds, and roots for human use were identified from the literature.

Clitoria ternatea Flower Extract Attenuates Postprandial Lipemia and Increases Plasma Antioxidant Status Responses to a High-Fat Meal Challenge in Overweight and Obese Participants

Simple Summary

Supplementation of high-fat meals with edible plants is the principal strategy to control postprandial dysmetabolism and inflammation. This study demonstrated that consumption of Clitoria ternatea flower extract (CTE) decreased postprandial serum triglyceride and serum free fatty acids, and improved plasma antioxidant status and glutathione peroxidase activity responses to a high-fat meal challenge in overweight and obese participants. However, CTE could not reduce the effect of HF meal-induced increase in postprandial glycemia and the level of pro-inflammatory cytokines. The findings of the present study suggest that CTE may be used as an effective ingredient to suppress postprandial lipemia and improve the antioxidant status in overweight and obese individuals that frequently consume HF diets.

Abstract

High-fat (HF) meal-induced postprandial lipemia, oxidative stress and low-grade inflammation is exacerbated in overweight and obese individuals. This postprandial dysmetabolism contributes to an increased risk of cardiovascular disease and metabolic disorders. Clitoria ternatea flower extract (CTE) possesses antioxidant potential and carbohydrate and fat digestive enzyme inhibitory activity in vitro. However, no evidence supporting a favorable role of CTE in the modulation of postprandial lipemia, antioxidant status and inflammation in humans presently exists. In the present study, we determine the effect of CTE on changes in postprandial glycemic and lipemic response, antioxidant status and pro-inflammatory markers in overweight and obese men after consumption of an HF meal. Following a randomized design, sixteen participants (age, 23.5 ± 0.6 years, and BMI, 25.7 ± 0.7 kg/m²) were assigned to three groups that consumed the HF meal, or HF meal supplemented by 1 g and 2 g of CTE. Blood samples were collected at fasting state and then at 30, 60, 90, 120, 180, 240, 300 and 360 min after the meal consumption. No significant differences were observed in the incremental area under the curve (iAUC) for postprandial glucose among the three groups. Furthermore, 2 g of CTE decreased the iAUC for serum triglyceride and attenuated postprandial serum free fatty acids at 360 min after consuming the HF meal. In addition, 2 g of CTE significantly improved the iAUC for plasma antioxidant status, as characterized by increased postprandial plasma FRAP and thiol levels. Postprandial plasma glutathione peroxidase activity was significantly higher at 180 min after the consumption of HF meal with 2 g of CTE. No significant differences in the level of pro-inflammatory cytokines (interleukin-6, interleukin-1β and tumor necrosis factor-α) were observed at 360 min among the three groups. These findings suggest that CTE can be used as a natural ingredient for reducing postprandial lipemia and improving the antioxidant status in overweight and obese men after consuming HF meals.

Postprandial Glycemia, Insulinemia, and Antioxidant Status in Healthy Subjects after Ingestion of Bread made from Anthocyanin-Rich Riceberry Rice

Riceberry rice, a gluten-free grain, contains many nutrient components, including carbohydrates, proteins, certain fatty acids, and micronutrients, as well as bioactive non-nutrient compounds, such as polyphenolic compounds. This study aimed to evaluate the effect of bread made from anthocyanin-rich Riceberry rice on the postprandial glycemic response, glucagon-like peptide-1 (GLP-1), antioxidant status, and subjective ratings of appetite. In the crossover design, 16 healthy participants (six men and 10 women) completed four sessions involving blood collection in the fasting state and at 30, 60, 90, 120, 150, and 180 min after food consumption (50 g of available carbohydrate) in a randomized order: 1) glucose solution, 2) wheat bread (WB), 3) Riceberry rice bread (RRB), and 4) Hom Mali bread (HMB). Consumption of RRB resulted in significantly lower postprandial plasma glucose concentration at 30 and 60 min when compared to HMB. No difference in postprandial glucose concentration between RRB and WB was observed. In addition, postprandial plasma insulin showed a significant decrease in the group which received RRB at 15 and 60 min, as compared to HMB. In comparison with 50 g of glucose, as a reference, the glycemic index (GI) of RRB, WB, and HMB was 69.3 ± 4.4, 77.8 ± 4.6, and 130.6 ± 7.9, respectively. Interestingly, the ferric-reducing ability of plasma (FRAP) level was shown to significantly increase after consumption of RRB. In the meantime, a significant decrease in the postprandial FRAP level was also observed following an intake of WB and HMB. All breads caused increases in the postprandial plasma protein thiol group and had similar effects on hunger, fullness, desire to eat, and satiety ratings. However, consumption of RBB, WB, and HMB did not change plasma GLP-1 and malondialdehyde (MDA) levels when compared to the baseline. The findings suggest that anthocyanin-rich Riceberry rice can be a natural ingredient for gluten-free bread which reduced glycemic response together with improvement of antioxidant status in healthy subjects.

Reducing the glycemic impact of carbohydrates on foods and meals: Strategies for the food industry and consumers with special focus on Asia

Type 2 diabetes is increasingly prevalent in Asia, which can be attributed to a carbohydrate-rich diet, consisting of foods in the form of grains, for example, rice, or a food product made from flours or isolated starch, for example, noodles. Carbohydrates become a health issue when they are digested and absorbed rapidly (high glycemic index), and more so when they are consumed in large quantities (high glycemic load). The principal strategies of glycemic control should thus aim to reduce the amount of carbohydrate available for digestion, reduce the rate of digestion of the food, reduce the rate of glucose absorption, and increase the rate of glucose removal from blood. From a food perspective, the composition and structure of the food can be modified to reduce the amount of carbohydrates or alter starch digestibility and glucose absorption rates via using different food ingredients and processing methods. From a human perspective, eating behavior and food choices surrounding a meal can also affect glycemic response. This review therefore identifies actionable strategies and opportunities across foods and meals that can be considered by food manufacturers or consumers. They are (a) using alternative ingredients, (b) adding functional ingredients, and (c) changing processing methods and parameters for foods, and optimizing (a) eating behavior, (b) preloading or co-ingestion of other macronutrients, and (c) meal sequence and history. The effectiveness of a strategy would depend on consumer acceptance, compatibility of the strategy with an existing food product, and whether it is economically or technologically feasible. A combination of two or more strategies is recommended for greater effectiveness and flexibility.

Impact of Clitoria ternatea (butterfly pea) flower on in vitro starch digestibility, texture and sensory attributes of cooked rice using domestic cooking methods

The effect of Clitoria ternatea flower (CTE) incorporated into cooked rice using domestic cooking methods on starch digestibility was determined. The incorporation of 1.25% and 2.5% (w/v) CTE caused a reduction in the starch digestibility of cooked rice using an electric rice cooker. In addition, there was significant alteration on the starch digestibility of cooked rice incorporated with 2.5% CTE using a microwave oven. Moreover, CTE significantly reduced the level of rapidly digestible starch and increased the level of undigested starch in cooked rice using an electric rice cooker. In the textural characteristics, the hardness of cooked rice with CTE remained unchanged, whereas a reduction in stickiness of cooked rice with CTE was observed. The sensory evaluation of cooked rice with CTE given by panelists demonstrated a good overall acceptability. Overall, the results show that CTE is a useful ingredient to incorporate with cooked rice for reduction of starch digestibility.

Butterfly Pea (Clitoria ternatea), a Cyclotide-Bearing Plant With Applications in Agriculture and Medicine

The perennial leguminous herb Clitoria ternatea (butterfly pea) has attracted significant interest based on its agricultural and medical applications, which range from use as a fodder and nitrogen fixing crop, to applications in food coloring and cosmetics, traditional medicine and as a source of an eco-friendly insecticide. In this article we provide a broad multidisciplinary review that includes descriptions of the physical appearance, distribution, taxonomy, habitat, growth and propagation, phytochemical composition and applications of this plant. Notable amongst its repertoire of chemical components are anthocyanins which give C. ternatea flowers their characteristic blue color, and cyclotides, ultra-stable macrocyclic peptides that are present in all tissues of this plant. The latter are potent insecticidal molecules and are implicated as the bioactive agents in a plant extract used commercially as an insecticide. We include a description of the genetic origin of these peptides, which interestingly involve the co-option of an ancestral albumin gene to produce the cyclotide precursor protein. The biosynthesis step in which the cyclic peptide backbone is formed involves an asparaginyl endopeptidase, of which in C. ternatea is known as butelase-1. This enzyme is highly efficient in peptide ligation and has been the focus of many recent studies on peptide ligation and cyclization for biotechnological applications. The article concludes with some suggestions for future studies on this plant, including the need to explore possible synergies between the various peptidic and non-peptidic phytochemicals.

Physicochemical Properties of Hom Nil (Oryza sativa) Rice Flour as Gluten Free Ingredient in Bread

Hom Nil (Oryza sativa), a Thai black rice, contains polyphenolic compounds which have antioxidant properties. The objective of this study was to investigate physicochemical properties of Hom Nil rice flour (HN) and its application in gluten free bread by using Hom Mali 105 rice flour (HM) as the reference. The results demonstrated that HN flour had significantly higher average particle sizes (150 ± 0.58 μm), whereas the content of amylose (17.6 ± 0.2%) was lower than HM flour (particle sizes = 140 ± 0.58 μm; amylose content = 21.3 ± 0.6%). Furthermore, HN contained higher total phenolic compounds (TPC) (2.68 ± 0.2 mg GAE/g flour), total anthocyanins (293 ± 30 mg cyanidin-3-glucoside/g flour), and the ferric reducing antioxidant power (FRAP) (73.5 ± 1.5 mM FeSO₄/g) than HM flour (TPC = 0.15 mg GAE/g flour and FRAP = 2.24 mM FeSO₄/g flour). In thermal properties, the onset temperature (To), the peak temperature (Tp) and the conclusion (Tc) temperature of HN flour were similar to the values of HM flour. However, HN flour had lower enthalpy change (ΔH) than HM flour. The results showed that HN flour had lower swelling power and higher solubility than HM flour at the temperature between 55 °C and 95 °C. In pasting properties, HN flour also showed lower peak, trough and breakdown viscosity than HM flour. In addition, the bread samples prepared by HN flour had higher value of hardness and lower value of cohesiveness than the bread prepared from HM flour. Taken together, the findings suggest that HN flour could be used as an alternative gluten-free ingredient for bread product.