Enzyme inhibitory activities of phenolic compounds in pecan and the effect on starch digestion

Current advances in the interaction mechanisms, nutritional role and functional properties of phenolic compound-starch complexes

This review explores starch-phenolic compound complexes' formation mechanisms, structural characteristics, and functional roles. These complexes alter starch properties, enhance its resistance to digestion, and modulate enzyme activity, with significant implications for glycemic control. A critical discussion of preparation methods and characterization techniques is presented, emphasizing their application in functional food design and health-oriented products. The review highlights the potential of these complexes to address metabolic disorders, offering valuable insights for advancing food science and nutrition.

Comparing gastric emptying of cellulose nanocrystals with sodium alginate and pectin using a dynamic in vitro stomach model

Cellulose nanocrystals (CNC) are increasingly recognized for their potential in various applications, including packaging, cosmetics, and biomedical engineering. Due to their gelation properties influenced by pH and ionic strength, CNC could impact gastric emptying and satiety, beneficial for managing obesity and diabetes. This study investigated the gastric emptying of CNC (4 % and 8 %, w/w) in comparison with sodium alginate (2 %, w/w) and pectin (2 %, w/w), exploring the effect of divalent cations (Ca2+ and Mg2+) using a dynamic gastric digestion model. CNC, in the presence of Ca2+ and Mg2+, formed a high-viscosity gel network under gastric conditions, leading to delayed gastric emptying. While alginate formed strong gels with Ca2+, it did not significantly delay gastric emptying due to the poor water-holding capacity of its gel network. Pectin showed minimal impact on gastric emptying. Among the treatments, the half-time (t1/2) of gastric emptying for 8 % CNC with Ca2+ was observed to be the longest at 215.4 ± 23.7 min, compared to the shortest times observed with pectin at 15.1 ± 1.4 min. The results suggest that different mechanisms are involved in the gastric emptying effect of different dietary fibers, and CNC is more effective than alginate and pectin assisting in promoting gastric retention and aiding in the management of body weight. This study also introduced a novel application of the dynamic gastric digestion model for estimating digestion energy expenditure, providing insights into the impact of dietary fiber on gastric emptying and satiety enhancement.

Bioaccessibility and Antidiabetic Potential of xique-xique and mandacaru Fruits in a Simulated Gastrointestinal Tract Model

This study evaluated the influence of gastrointestinal digestion on the bioaccessibility and antidiabetic potential of xique-xique (Pilosocereus gounellei) and mandacaru (Cereus jamacaru) fruits. After digestion, the content of total phenolics and flavonoids reduced by 58.3 and 73.51% in xique-xique and 48.33 and 88.43% in mandacaru. In addition, compounds such as rutin, ρ-coumaric acid, catechin and epicatechin reduced during digestion for both fruits. The antioxidant potential by the ABTS assay increased by 153.3% for xique-xique and 273.46% for mandacaru in the intestinal phase. However, using the ORAC assay, the antioxidant potential of xique-xique reduced from 255.42 to 112.17 μmol TE g-1. The capacity of xique-xique fruit to reduce α-amylase activity reduced 23.71-fold after digestion, but the potential to inhibit α-glucosidase increased 17.8-fold. The antiglycation potential reduced in both fruits after the in vitro gastrointestinal digestion. Thus, the bioaccessibility of the phenolic compounds from the fruits, as well as their functional potential, were influenced by the digestive process, as well as by the sample evaluated.

Resistant starch from yam: Preparation, nutrition, properties and applications in the food sector

Yam is a significant staple food and starch source, particularly in tropical and subtropical regions, holding the fourth position among the world's top ten tuber crops. Yam tubers are rich in essential nutrients and a diverse range of beneficial plant compounds, which contribute to their multifaceted beneficial functions. Furthermore, the abundant starch and resistant starch (RS) content in yam can fulfil the market demand for RS. The inherent and modified properties of yam starch and RS make them versatile ingredients for a wide range of food products, with the potential to become one of the most cost-effective raw materials in the food industry. In recent years, research on yam RS has experienced progressive expansion. This article provides a comprehensive summary of the latest research findings on yam starch and its RS, elucidating the feasibility of commercial RS production and the technology's impact on the physical and chemical properties of starch. Yam has emerged as a promising reservoir of tuber starch for sustainable RS production, with thermal, chemical, enzymatic and combination treatments proving to be effective manufacturing procedures for RS. The adaptability of yam RS allows for a wide range of food applications.

Interactions between corn starch and lingonberry polyphenols and their effects on starch digestion and glucose transport

This study investigated the interaction mechanism between corn starch (CS) and lingonberry polyphenols (LBP) during starch gelatinization, focusing on their effects on starch structure and physicochemical properties. Moreover, it explored the effect of this interaction on starch digestion and glucose transport. The results indicated that LBP interacted non-covalently with CS during starch gelatinization, disrupted the short-range ordered structure of starch, decreased gelatinization enthalpy of starch, and formed a dense network structure. Furthermore, the incorporation of LBP remarkably reduced the digestibility of CS. In particular, the addition of 10 % LBP decreased the terminal digestibility (C∞) from 77.87 % to 60.43 % and increased the amount of resistant starch (RS) by 21.63 %. LBP was found to inhibit α-amylase and α-glucosidase in a mixed manner. Additionally, LBP inhibited glucose transport in Caco-2 cells following starch digestion. When 10 % LBP was added, there was a 34.17 % decrease in glucose transport compared with starch digestion without LBP. This study helps establish the foundation for the development of LBP-containing starch or starch-based healthy foods and provides new insights into the mechanism by which LBP lowers blood glucose.

Novel strategy to the characterization and enhance the glycemic control properties of walnut-derived peptides via zinc chelation

This study aimed to utilize zinc coordination to promote the hypoglycemic and antioxidant properties of walnut-derived peptides, such as walnut protein hydrolysate (WPH) and Leu-Pro-Leu-Leu-Arg (LPLLR, LP5), of which LP5 was previously identified from WPH. The optimal conditions for the chelation were a peptide-to-zinc ratio of 6:1, pH of 9, duration of 50 min, and temperature of 50 °C. The WPH-Zn and LP5-Zn complexes increased the α-glucosidase inhibition, α-amylase inhibition, and antioxidant activity more than WPH and LP5 (p < 0.05). In particular, the antioxidant activity of WPH-Zn was superior to LP5-Zn. This is attributable to the WPH containing more aromatic amino acids, carboxylate groups and the imidazole groups, which implies its capacity to potentially coordinate with Zn2+ to form the WPH-Zn complex. Moreover, particle size, zeta potential, and scanning electron microscope indicated that the chelation of Zn2+ by peptides led to intramolecular and intermolecular folding and aggregation.

Inhibitory effect of extracts from edible parts of nuts on α-amylase activity: a systematic review

Elevated blood glucose concentration is a risk factor for developing metabolic dysfunction and insulin resistance, leading to type 2 diabetes and cardiovascular diseases. Nuts have the potential to inhibit α-amylase activity, and so lower postprandial glucose, due to their content of polyphenols and other bioactive compounds. We conducted a systematic literature review to assess the ability of extracts from commonly consumed edible parts of nuts to inhibit α-amylase. Among the 31 included papers, only four utilised human α-amylases. These papers indicated that polyphenol-rich chestnut skin extracts exhibited strong inhibition of both human salivary and pancreatic α-amylases, and that a polyphenol-rich almond skin extract was a potent inhibitor of human salivary α-amylase. The majority of the reviewed studies utilised porcine pancreatic α-amylase, which has ∼86% sequence homology with the corresponding human enzyme but with some key amino acid variations located within the active site. Polyphenol-rich extracts from chestnut, almond, kola nut, pecan and walnut, and peptides isolated from cashew, inhibited porcine pancreatic α-amylase. Some studies used α-amylases sourced from fungi or bacteria, outcomes from which are entirely irrelevant to human health, as they have no sequence homology with the human enzyme. Given the limited research involving human α-amylases, and the differences in inhibition compared to porcine enzymes and especially enzymes from microorganisms, it is recommended that future in vitro experiments place greater emphasis on utilising enzymes sourced from humans to facilitate a reliable prediction of effects in intervention studies.

Effects of purple potato anthocyanins on the in vitro digestive properties of starches of different crystalline types

This study explored the potential of purple potato anthocyanins (PPAs) in regulating the digestive properties of starches of various crystalline types. In vitro digestion experiments indicated that PPAs inhibit the hydrolysis of rice starch (A-type) better than that of garden pea starch (C-type) and potato starch (B-type). Further structural assessment of different PPA-starch systems showed that PPAs and starch likely interact through non-covalent bonds, resulting in structural changes. Microstructural changes observed in the starches were consistent with the in vitro digestion results, and the chain length and proportions of short/long chains in amylopectin molecules affected the binding strengths and interaction modes between PPAs and starch. Hence, the three starches differed in their PPA loading efficiency and digestibility. These discoveries contribute to a deeper understanding of the mechanisms underlying the inhibition of starch digestibility by PPAs. They can aid the formulation of value-added products and low-glycemic-index foods.

Polymorphic nanostarch-mediated assembly of bioactives

Starch as an edible, biosafe, and functional biopolymer, has been tailored at nanoscale to deliver bioactive guests. Nanostarches fabricated in various morphologies including nanosphere, nanorod, nanoworm, nanovesicle, nanopolyhedron, nanoflake, nanonetwork etc., enable them to assemble different kinds of bioactives due to structural particularity and green modification. Previous studies have reviewed nanostarch for its preparation and application in food, however, no such work has been done for the potential of delivery system via polymorphic nanostarches. In this review, we focus on the merits of nanostarch empowered by multi-morphology for delivery system, and also conclude the assembly strategies and corresponding properties of nanostarch-based carrier. Additionally, the advantages, limitations, and future perspectives of polymorphic nanostarch are summarized to better understand the micro/nanostarch architectures and their regulation for the compatibility of bioactive molecules. According to the morphology of carrier, nanostarch effectively captures bioactives on the surface and/or inside core to form tight complexes, which maintains their stability in the human microenvironment. It improves the bioavailability of bioactive guests by different assembly approaches of carrier/guest surface combination, guest@carrier embedment, and nanostarch-mediated encapsulation. Targeted release of delivery systems is stimulated by the microenvironment conditions based on the complex structure of nanostarch loaded with bioactives.

Fermentation of resistant starch from the starch-ferulic acid inclusion complex compared with high-amylose corn starch

Fermentation of resistant starch from the starch-ferulic acid inclusion complex, one representative of the starch-polyphenol inclusion complex, was investigated in this study. It was found that this complex-based resistant starch, high-amylose corn starch and the mixture of ferulic acid and high-amylose corn starch were mainly utilized at the initial 6 h as indicated by the gas production and pH. Besides, the supplement of high-amylose corn starch, the mixture and the complex promoted production of short-chain fatty acids (SCFAs), reduced the ratio of Firmicutes/Bacteroidetes (F/B) and selectively stimulated the proliferation of some beneficial bacteria. Specifically, the production of SCFAs in the control and high-amylose starch, mixture and complex groups was 29.33 mM, 140.82 mM, 144.12 mM, and 167.4 mM after fermentation for 48 h, respectively. Moreover, the F/B ratio of those groups was 1.78, 0.78, 0.8 and 0.69, respectively. These results suggested that the supplement of the complex-based resistant starch led to the most SCFAs and the lowest F/B ratio (P < 0.05). Moreover, the complex group had the largest abundance of beneficial bacteria, including Bacteroides, Bifidobacterium and Lachnospiraceae_UCG-001 (P < 0.05). In summary, the resistant starch from the starch-ferulic acid inclusion complex exhibited stronger prebiotic activity than high-amylose corn starch and the mixture.