Susceptibility of annealed starches to hydrolysis by α-amylase and glucoamylase

Plastein reaction augments the metal chelating capabilities of silver carp (Hypophthalmichthys molitrix) hydrolysates: Unlocking the chemical modification mechanism

Plastein reaction mechanisms and the alteration of its product properties have been studied for decades. This study investigated the plastein-mediated modifications in silver carp protein hydrolysate (SCPH) from both mechanistic and functional perspectives. Unlike prior research, this investigation uncovered that hydrogen bonding supplemented the dominant hydrophobic interactions in plastein's mechanism for the first time, as supported by peptide concentrations, molecular weight, amino acids, chemical forces, and peptide sequence by LC-MS/MS. This innovative reaction mechanism cascaded into the enhancement of SCPH functional attributes. Plastein induced increased COOH in SCPH's side-chain groups significantly enhanced Fe2+ (from 4.49 to 14.12 %) and Zn2+ (from 53.53 to 64.47 %) chelation. Moreover, the elevated DPPH (17.56 %-23.97 %) and hydroxyl radical (68.49 %-79.32 %) scavenging power indicated a broader improvement in SCPH with plastein. In SCPH, plastein elucidated reaction intricacies and enhanced its utility, propelling SCPH into a realm of extended potential.

Oil structuring from porous starch to powdered oil: Role of multi-scale structure in the oil adsorption and distribution

Oil structuring from porous starch is a potential alternative for the industrial production of powdered oil, but their relationship between starch multi-scale structure and oil adsorption characteristics was not clear. This study compared the role of multi-scale structure of porous starch (PS) prepared by normal and waxy maize starch in the oil adsorption. Waxy maize porous starch exhibited higher oil adsorption capacity (32.43 %-98.71 %) and more oil distributed on the surface of granules than normal maize porous starch, resulting from the more pores, larger specific surface area (1.01-1.53 m2/g), and pore size (8.45-9.32 nm). The enzymolysis time of native starch dominated oil distribution, leading to different granule adhesion and aggregation state. Pearson correlation analysis further showed oil adsorption capacity was negatively correlated with particle size, but positively correlated with enzymolysis rate and specific surface area of PS. The formation of powdered oil was mainly through the physical adsorption, including surface adsorption and pore adsorption. These findings could provide a promising route for the preparation of powdered oil with controlled multi-scale structure of PS.

Hydrothermal processes and simultaneous enzymatic hydrolysis in the production of modified cassava starches with porous-surfaces

The amylolytic action of α-amylase and amyloglucosidase has been directly implemented in native cassava starches for the formation of cassava microporous granules with unsatisfactory results, however, its incidence in hydrothermally treated granules has never been evaluated. The effect of hydrothermal processes and simultaneous enzymatic hydrolysis on the physicochemical, morphological and structural properties of native cassava starch was evaluated. Native cassava starch presented a rigid, smooth surface, and was exempt from porosities, whereas hydrothermal processes altered the semicrystalline order and increasing the size and number of pores and increasing the size (4.11 ± 0.09 nm) and volume of pores (0.82 ± 0.00 cm3/g × 10-3). The hydrothermal action followed by enzymatic processes with α-amylase and amyloglucosidase, augmented the processes of internal degradation (endo-erosion) and pore widening (exo-erosion), improving the hydrophilic properties compared to the hydrothermal treatment. Likewise, the hydrothermally process followed by enzymatic hydrolysis for 24 h (HPS + EMS-24) increased the degradation of the amorphous lamellae, consistent with a significant decrease in amylose content. This same dual treatment increased the pore size at 17.68 ± 0.13 nm relative to the native counterpart; therefore, they are considered an effective method in the development of modified cassava starches with porous surfaces.

High-amylose maize starch: Structure, properties, modifications and industrial applications

High-amylose maize refers to a special type of maize cultivar with a 50 %-90 % amylose content of the total starch. High-amylose maize starch (HAMS) is of interest because it possesses unique functionalities and provides many health benefits for humans. Therefore, many high-amylose maize varieties have been developed via mutation or transgenic breeding approaches. From the literature reviewed, the fine structure of HAMS is different from the waxy and normal corn starches, influencing its gelatinization, retrogradation, solubility, swelling power, freeze-thaw stability, transparency, pasting and rheological properties, and even in vitro digestion. HAMS has undergone physical, chemical, and enzymatical modifications to enhance its characteristics and thereby broaden its possible uses. HAMS has also been used for the benefit of increasing resistant starch levels in food products. This review summarizes the recent developments in our understanding of the extraction and chemical composition, structure, physicochemical properties, digestibility, modifications, and industrial applications of HAMS.

Insight into the incredible effects of microwave heating: Driving changes in the structure, properties and functions of macromolecular nutrients in novel food

Microwave heating technology performs the characteristics of fast heating, high efficiency, green energy saving and easy control, which makes it deeply penetrate into the food industry and home cooking. It has the potential to alter the appearance and flavor of food, enhance nutrient absorption, and speed up the transformation of active components, which provides an opportunity for the development of innovation foods. However, the change of food driven by microwave heating are very complex, which often occurs beyond people's cognition and blocks the development of new food. It is thus necessary to explore the transformation mechanism and influence factors from the perspectives of microwave technology and food nutrient diversity. This manuscript focuses on the nutritional macromolecules in food, such as starch, lipid and protein, and systematically analyzes the change rule of structure, properties and function under microwave heating. Then, the flavor, health benefits, potential safety risks and bidirectional allergenicity associated with microwave heating are fully discussed. In addition, the development of new functional foods for health needs and future market based on microwave technology is also prospected. It aims to break the scientific fog of microwave technology and provide theoretical support for food science to understand the change law, control the change process and use the change results.

Effect of Single and Dual Hydrothermal Treatments on the Resistant Starch Content and Physicochemical Properties of Lotus Rhizome Starches

Heat-moisture treatment (HMT) changed the morphology and the degree of molecular ordering in lotus rhizome (Nelumbo nucifera Gaertn.) starch granules slightly, leading to some detectable cavities or holes near hilum, weaker birefringence and granule agglomeration, accompanied with modified XRD pattern from C- to A-type starch and lower relative crystallinity, particularly for high moisture HMT modification. In contrast, annealing (ANN) showed less impact on granule morphology, XRD pattern and relative crystallinity. All hydrothermal treatment decreased the resistant starch (from about 27.7–35.4% to 2.7–20%), increased the damage starch (from about 0.5–1.6% to 2.4–23.6%) and modified the functional and pasting properties of lotus rhizome starch pronouncedly. An increase in gelatinization temperature but a decrease in transition enthalpy occurred after hydrothermal modification, particularly for hydrothermal modification involved with HMT. HMT-modified starch also showed higher pasting temperature, less pronounced peak viscosity, leading to less significant thixotropic behavior and retrogradation during pasting-gelation process. However, single ANN treatment imparts a higher tendency of retrogradation as compared to native starch. For dual hydrothermally modified samples, the functional properties generally resembled to the behavior of single HMT-modified samples, indicating the pre- or post-ANN modification had less impact on the properties HMT modified lotus rhizome starch.

Physicochemical and digestive properties of A- and B-type granules isolated from wheat starch as affected by microwave-ultrasound and toughening treatment

In this study, the effect of microwave-ultrasound or/and toughening treatment on the physicochemical, structural properties, and in vitro digestibility of A- and B-type granules isolated from wheat starch were investigated. From the SEM, microwave-ultrasound and toughening treatment (MU-T) led to the appearance of irregular and disrupted structure significantly and an increment in the resistant starch content of A- and B-type granule. Furthermore, the MU-T starch possessed the lowest swelling power, light transmittance, and gelatinization temperature range (T_c -T_o) and the highest ΔH. After MU-T, the relative crystallinity (RC) of X-ray pattern, Fourier transform infrared ratio of 1047/1022 cm^-1, and the content of double helix and single helix of ¹³C CP/MAS NMR had increased significantly. In particular, there was a difference in the content of RS and SDS between A-starch granules and B-starch granules as well as their changes after modification (from 69.305% to 82.93 for A-starch and form 74.97% to 88.17 for B-starch, respectively), which was a similar trend with RC and helix content. This study indicated that, for both A-type granule and B-type granule starches, microwave-ultrasound and toughening treated samples had unique properties compared to singly modified starches.

The addition of alpha amylase improves the quality of Chinese dried noodles

The effect of α-amylase on the quality attributes of Chinese dried noodles (CDN) was investigated. Adding α-amylase markedly decreased the cooking time and cooking loss of CDN at the level of 12.5 (mg/100 g flour). The elasticity of CDN was increased significantly (P < 0.05) after adding α-amylase. The firmness of noodles with 12.5 mg α-amylase per 100 g flour showed no obvious change compared to the control, whereas it decreased significantly (P < 0.05) when the amount of α-amylase increased to 25 (mg/100 g flour). In addition, the chewiness of CDN with 12.5 mg α-amylase per 100 g flour increased, while it showed a significant (P < 0.05) decreasing trend with further increased α-amylase levels. Starch structural and thermal properties were also changed by α-amylase, which showed increased relative crystallinity, swelling power, but decreased pasting property. The changed starch property restrained the cross-linking of gluten. The decrease in optimal cooking time and increase in elasticity of CDN were due to the increased swelling power and decreased peak time of the starch. In addition, the decreased setback of starch and protein cross-linking degree were responsible for the decreased firmness and chewiness of CDN with α-amylase ranging from 25 to 50 mg/100 g flour. Overall, α-amylase could be used as a functional additive to improve the quality of CDN when the amount was at 12.5 mg/100 g flour.

The Effect of Germinated Sorghum Extract on the Pasting Properties and Swelling Power of Different Annealed Starches

Starches were extracted from chickpea (C.P.), corn (C.S.), Turkish bean (T.B.), sweet potato (S.P.S.), and wheat starches (W.S.). These starches exhibited different amylose contents. The extracted starches were annealed in excess water and in germinated sorghum extract (GSE) (1.0 g starch/9 mL water). The α-amylase concentration in the GSE was 5.0 mg/10 mL. Annealing was done at 40, 50, and 60 °C for 30 or 60 min. The pasting properties of annealed starches were studied using Rapid Visco-Analyzer (RVA), in addition to the swelling power. These starches exhibited diverse pasting properties as evidenced by increased peak viscosity with annealing, where native starches exhibited peak viscosity as: 2828, 2438, 1943, 2250, and 4601 cP for the C.P., C.S., T.B., W.S., and S.P.S., respectively, which increased to 3580, 2482, 2504, 2514, and 4787 cP, respectively. High amylose content did not play a major role on the pasting properties of the tested starches because sweet potato starch (S.P.S.) (22.4% amylose) exhibited the highest viscosity, whereas wheat starch (W.S.) (25% amylose) had the least. Therefore, the dual effects of granule structure and packing density, especially in the amorphous region, are determinant factors of the enzymatic digestion rate and product. Swelling power was found to be a valuable predictive tool of amylose content and pasting characteristics of the tested starches. The studied starches varied in their digestibility and displayed structural differences in the course of α-amylase digestion. Based on these findings, W.S. was designated the most susceptible among the starches and S.P.S. was the least. The most starch gel setback was observed for the legume starches, chickpeas, and Turkish beans (C.P. 2553 cP and T.B. 1172 cP). These results were discussed with regard to the underlying principles of swelling tests and pasting behavior of the tested starches. Therefore, GSE is an effortless economic technique that can be used for starch digestion (modification) at industrial scale.

Characterization and expression in Pichia pastoris of a raw starch degrading glucoamylase (GA2) derived from Aspergillus flavus NSH9

The Aspergillus flavus NSH9 gene, encoding a pH and thermostable glucoamylase with a starch binding domain (SBD), was expressed in Pichia pastoris to produce recombinant glucoamylase (rGA2). The full-length glucoamylase gene (2039 bp), and cDNA (1839 bp) encode a 612 amino acid protein most similar to glucoamylase from Aspergillus oryzae RIB40; the first 19 amino acids are presumed to be a signal peptide for secretion, and the SBD is at the C-terminal. The cDNA was successfully secreted by Pichia at 8.23 U mL^-1, and the rGA2 was found to be: a 80 kDa monomer, stable from pH 3.0-9.0, with optimum catalytic activity at pH 5.0, active at temperatures up to 80°C (rGA2 retained 58% of its activity after 60 min of incubation at 70°C), and metal ions such as Na⁺, K⁺, Ca⁺⁺ and Mg⁺⁺ enhanced rGA2 enzyme activity. The starch degrading ability of rGA2 was also observed on raw sago starch and where prolonged incubation generated larger, deeper, holes on the starch granules, indicating rGA2 is an excellent candidate for industrial starch processing applications.

Engineering Synthetic Microbial Communities through a Selective Biofilm Cultivation Device for the Production of Fermented Beverages

Production of Cambodian rice wine involves complex microbial consortia. Indeed, previous studies focused on traditional microbial starters used for this product revealed that three microbial strains with complementary metabolic activities are required for an effective fermentation, i.e., filamentous fungi (Rhizopus oryzae), yeast (Saccharomycescerevisiae), and lactic acid bacteria (Lactobacillusplantarum). Modulating the ratio between these three key players led to significant differences, not only in terms of ethanol and organic acid production, but also on the profile of volatile compounds, in comparison with natural communities. However, we observed that using an equal ratio of spores/cells of the three microbial strains during inoculation led to flavor profile and ethanol yield close to that obtained through the use of natural communities. Compartmentalization of metabolic tasks through the use of a biofilm cultivation device allows further improvement of the whole fermentation process, notably by increasing the amount of key components of the aroma profile of the fermented beverage (i.e., mainly phenylethyl alcohol, isobutyl alcohol, isoamyl alcohol, and 2-methyl-butanol) and reducing the amount of off-flavor compounds. This study is a step forward in our understanding of interkingdom microbial interactions with strong application potential in food biotechnology.

The Comparison of Structural, Physicochemical, and Digestibility Properties of Repeatedly and Continuously Annealed Sweet Potato Starch

In order to investigate the varied effects of repeated annealing treatment (RANN) and continuous annealing treatment (CANN) on the structural, physicochemical, and digestibility properties of the sweet potato. The 75% starch-water suspensions were prepared and incubated at 65 °C for 8 cycles and 96 hr. The results exhibited that RANN and CANN did not influence the starch granules and polarization cross obviously. The crystal type of RANN and CANN starches still maintained A-type, while the relative crystallinity increased. The solubility, swelling power, peak viscosity and breakdown of RANN and CANN starches decreased, but the gelatinization transition temperatures, trough viscosity, final viscosity, setback, and pasting temperatures of starches increased after annealing treatments. Furthermore, RANN and CANN decreased the RS and RS + SDS contents with the increase of annealing cycles and time. The RANN was more effective in modification of the crystallinity, solubility, swelling power, pasting, gelatinization transition temperatures and enthalpy, and digestibility of starch before four times compared with the CANN ones. By and large, RANN may be a potential way for modification of structural, physicochemical and digestibility properties. PRACTICAL APPLICATION: The described RANN and CANN starch provide new ideas for the study of modified starch. Furthermore, this study revealed the mechanism of annealing treatment and it was concluded that the repeated annealing treatment could provide a new potential way for the modification of starch.

Some physico-chemical and thermodynamic characteristics of maize starches hydrolyzed by glucoamylase

Glucoamylolysis of maize starch at 55 °C has been studied by means of scanning electron microscopy (SEM), wide-angle X-ray diffraction spectroscopy (WAXD), and differential scanning calorimetry (DSC). It was found that hydrolysis is accompanied by changes in thermodynamic parameters of diluted aqueous dispersions of partially hydrolyzed starches. Such changes are ensured by two processes directly from hydrolysis and accompanying annealing. At relatively low degrees of hydrolysis (less than 30%), changes in thermodynamic parameters are mainly controlled by annealing. At the same time, at high degrees of hydrolysis (more than 40%), the main contribution to changes in thermodynamic parameters of partially hydrolyzed starch granules is due to the hydrolysis itself. It has been established that the main controlling parameter is the thickness of crystalline lamellae L_crl, which, when annealed, increases, but tends to decrease at deeper glucoamylolisis. It has been established that the thickness L_crl of crystalline lamellae, which increases with annealing, but shows a tendency to decrease with deeper glucoamylolysis is the most representative parameter of changes in maize starch after hydrolysis.

Adsorption of Tea Polyphenols using Microporous Starch: A Study of Kinetics, Equilibrium and Thermodynamics

Microporous starch (MPS) granules were formed by the partial hydrolysis of starch using α–amylase and glucoamylase. Due to its biodegradability and safety, MPS was employed to adsorb tea polyphenols (TPS) based on their microporous characteristics. The influences of solution pH, time, initial concentration and temperature on the adsorptive capacity were investigated. The adsorption kinetics data conformed to the pseudo second–order kinetics model, and the equilibrium adsorption data were well described by the Langmuir isotherm model. According to the fitting of the adsorption isotherm formula, the maximum adsorption capacity of TPS onto MPS at pH 6.7 and T = 293 K was approximately 63.1 mg/g. The thermodynamic parameters suggested that the adsorption of TPS onto MPS was spontaneous and exothermic. Fourier transform infrared (FT–IR) analysis and the thermodynamics data were consistent with a physical adsorption mechanism. In addition, MPS-loaded TPS had better stability during long-term storage at ambient temperature.

Optimizing Gastrointestinal Integrity in Poultry: The Role of Nutrients and Feed Additives

Immunomodulation of the immune system by stimulating or suppressing one or both arms, is an emerging concept driven by the understanding of the host defense system. In particular, the gastrointestinal tract (GIT) functions not only as a site for digestion and absorption of nutrients but also acts as a metabolic and immunological organ. This serves as a barrier against abnormal presentation of luminal constituents, caused by dysfunctional intestinal epithelial barrier, to the mucosal immune system. Invasion by pathogens in the case of disease or stress or a massive influx of commensal bacteria overcomes the defensive mechanisms, resulting in the full activation of local dendritic cells and the expression of co-stimulatory molecules and pro-inflammatory cytokines. A growing body of literature demonstrates the immune benefits of increasing the intake of specific nutrients. This strategy involves formulating diets that encompass the bioavailability and utilization of nutrients from various food sources and understanding the dynamics of the macro and micronutrients to support all physiological functions as well as maintaining the function of the immune cells. The nature and type of feed ingredients may also play some roles on the integrity of the GIT of birds. Because dietary intake or nutritional status as well as nutrient requirements may be altered as a result of disease or stress, this may eventually alter the gut microflora and intestinal mucosal integrity, resulting in a compromised barrier of the intestinal epithelium. The weakening of the intestinal integrity could result in an increase in bacterial adherence to the mucosa, bacterial translocation, susceptibility to opportunistic bacterial infection, and mis-appropriation of nutrients. In this chapter, we will discuss the role of dietary energy and nutrients as substrates that have the potential to influence GIT's health and integrity and their roles, directly or indirectly, in modulating bird's ability to be resilient or resist infection.

Effects of Dual Modification with Succinylation and Annealing on Physicochemical, Thermal and Morphological Properties of Corn Starch

The objective of this study was to investigate the effects of annealing, succinylation, and a dual modification process (succinylation⁻annealing) on the physicochemical, thermal, and morphological properties of corn starch. Specifically, the properties of interest were the water-binding capacity (WBC), swelling power, paste clarity, solubility, pasting properties, stability ratio, and thermal and morphological characteristics. The dual modification process increased the physicochemical properties (WBC, swelling power, peak viscosity, and paste clarity) and increased the gelatinization temperature and gelatinization enthalpy (∆H), but had no effect on the morphological properties and X-ray diffraction patterns. A comparison of samples, made using each of the processes, showed that dual modification increased the stability ratio (more stable viscosity under thermal and shear stress), which was 0.69 for dual modified starch, compared with 0.64, 0.58 and 0.44 for native, succinylated, and annealed starches, respectively. The findings of the present study are of potential use in the food industry.

Impact of Microbial Composition of Cambodian Traditional Dried Starters (Dombea) on Flavor Compounds of Rice Wine: Combining Amplicon Sequencing With HP-SPME-GCMS

Dombae is a traditional ferment starter which has been used for starchy based wine production in Cambodia. However, the production technology of rice wine in Cambodia is not optimized. The current study aimed to investigate the microbiota associated in five ferment starters and the effect of a traditional fermentation process using a metagenomics sequencing analysis and HS-SPME-GCMS for the characterization of the aromatic profiles at the end of fermentation. Most of bacteria identified in this study were lactic acid bacteria including Weissella cibaria, Pediococcus sp. MMZ60A, Lactobacillus fermentum, and Lactobacillus plantarum. Saccharomyces cerevisiae and Saccharomycopsis fibuligera were found to be abundant yeasts while the only amylolytic filamentous fungus was Rhizopus oryzae. A total of 25 aromatic compounds were detected and identified as esters, alcohols, acids, ketones and aldehydes. The alcohol group was dominant in each rice wine. Significant changes were observed at the level of microbial communities during fermentation, suggesting microbial succession for the assimilation of starch and subsequently assimilation of fermentation by-products leading to the production of flavor compounds. At this level, the presence of Weissella, Pediococcus, and Lactobacillus genus was strongly correlated with most of the flavor compounds detected.

Physicochemical characteristics, ATR-FTIR molecular interactions and in vitro starch and protein digestion of thermally-treated whole pulse flours

Hydrothermal treatments, annealing (ANN) and heat moisture treatment (HMT) were applied to four whole pulse flours (black bean, broad bean, chickpea and lentil) with the aim to increase their slow digestible (SDS) and resistant starch (RS) fractions. In order to assess differences in their molecular interactions, they were analyzed and compared by ATR-FTIR before and after in vitro digestion. Both hydrothermal treatments promoted changes on starch granular architecture, being reflected on their thermal and pasting properties, that where positively correlated with their amylose and protein contents (R=0.96, P<0.01). Overall, the proposed hydrothermal treatments increased their SDS and RS fractions, but they had different effect on their in vitro protein digestion. The ATR-FTIR analysis of cooked flours before and after digestion showed that thermal treatments promoted new physical interactions at molecular scale between starch and proteins, that were correlated with the amount of RS fraction. The outcomes of this study could help to understand the slow digestion properties and possible interactions of the flour components in these four pulses.