Effect of porcine plasma protein hydrolysates on long-term retrogradation of corn starch

Quality analysis of dough and steamed bread under various freezing conditions

Freezing is a crucial step in the process of frozen foods. In this study, the effects of different freezing methods, including liquid nitrogen immersion freezing (LF), quick-freezing machine freezing (QF), packaging immersion freezing (PF), and ultralow temperature refrigerator freezing (UF), and freezing time (0, 15, 30, and 60 days) on the textural properties, dynamic rheological properties, water distribution, and structure of dough and the quality of end steamed bread were evaluated. Freezing resulted in a decline in the physicochemical properties of dough. UF- and QF-doughs had higher storage modulus and loss modulus, compared with PF- and LF-doughs. LF enhanced the textural attributes of the dough, resulting in reduced hardness and increased springiness. At 15 days of freezing, QF- and LF-doughs exhibited a compact and continuous structure with a smooth surface. Additionally, the correlation analysis elucidated that the weight loss rate and the bound water content of the dough had discernible impacts on the texture of both the dough and the resulting steamed bread. Overall, LF demonstrated a relatively high freezing efficiency and effectively maintained the quality of the dough for up to 15 days of freezing. These results offer valuable insights for the applications of freezing methods and time in frozen foods.

A comparative study on the gel and structural characteristics of starch from three rice varieties when combined with Mesona chinensis polysaccharides

Mesona chinensis polysaccharide (MCP) has excellent gel-forming characteristic, previous studies showed that MCP could affect the gelling and structural properties of rice starch, but the effect of MCP on rice starch from different types is not clarified. In this study, the effects of MCP on the pasting, rheological, and structural characteristics of glutinous rice starch (GRS), japonica rice starch (JRS), and indica rice starch (IRS) were investigated. The results showed that GRS-MCP has the best viscosity, its peak and final viscosities are higher than JRS-MCP and IRS-MCP. The gel network structure was enhanced by MCP in the order of IRS > JRS > GRS, which was reflected by greater elasticity, higher gel strength and hardness, and less free water in JRS-MCP and IRS-MCP. MCP also enhanced the ordered structure and thermal stability of the three starch gels, which is conducive to their application in the market. These findings provide new theoretical insights to produce rice starch-based foods.

Exploring the effect of corn starch/pea protein blending on the physicochemical and structural properties of biopolymer films and their aging resistance

This study investigated the potential effect of blending corn starch and pea protein isolate in various ratios (100:0, 70:30, 50:50, 30:70, and 0:100) on the aging properties of biodegradable films. Unlike previous research, the focus was on the often-overlooked aspect of film aging. Fourier-transform infrared spectroscopy and X-ray diffraction demonstrated the physical blending of corn starch and pea protein, along with chemical bonding and conformational changes. The optical and microstructural properties showed the formation of smooth, homogeneous films with good compatibility between the polymers. The water resistance, barrier, and mechanical properties corresponding to the intrinsic nature of protein polymers showed a minimized fluctuations in film properties as film ages, with a reduction of at least twice when protein is added. Remarkably, the blend with a ratio of 30:70 demonstrated the most stable properties during aging. These results demonstrated that blending the pea protein isolate was favorable for delaying the retrogradation and recrystallization of corn starch films. Understanding how these blends influence the aging characteristics of films is not only a novel contribution to the scientific community but also holds practical significance, potentially opening a potential for applications in various industries.

Esterified wheat bran: Physicochemical properties, structure and quality improvement of Chinese steamed bread during refrigerated storage

To develop the application of wheat bran and improve the nutrition and anti-staling capacity of Chinese steamed bread (CSB), oleic acid-esterified wheat bran (OWB) was prepared by esterification of wheat bran with oleic acid, and its physicochemical properties, structure, and quality improvement for CSB during refrigerated storage were investigated. The hydrophilic-lipophilic balance value of OWB was 16.0, the maximum degree of substitution was 0.146, and its emulsifying capacity was similar to that of glycerol monostearate. The starch gelatinization degree of CSB containing 3 % OWB and the control decreased by 19.55 % and 27.12 % within 7 days of refrigerated storage, respectively, while the hardness of CSB with OWB was lower than that with wheat bran. OWB inhibited starch recrystallization and increased bound water in the corresponding CSB, which effectively delayed starch retrogradation. OWB had a positive emulsifying capacity and showed potential as a functional material for preventing retrogradation of starch-based foods.

Effects of soaking glutinous sorghum grains on physicochemical properties of starch

Glutinous sorghum grains were soaked (60-80 °C, 2-8 h) to explore the effects of soaking, an essential step in industrial processing of brewing, on starch. As the soaking temperature increased, the peak viscosity and crystallinity of starch gradually decreased, while the enzymatic hydrolysis rate and storage modulus first increased and then decreased. At 70 °C, the content of amylose, the enzymatic hydrolysis rate of starch, and the final viscosity first increase and then decrease with the increase of soaking time, reaching their maximum at 6 h, increased by 53.1 %, 11.0 %, and 10.4 %, respectively, as compared with the non-soaked sample. At 80 °C (4 h), the laser confocal microscopy images showed a network structure formed between the denatured protein chains and the leached-out amylose chains. The molecular weights of starch before and after soaking were all in the range of 3.82-8.98 × 107 g/mol. Since 70 °C is lower than that of starch gelatinization and protein denaturation, when soaking for 6 h, the enzymatic hydrolysis rate of starch is the highest, and the growth of miscellaneous bacteria is inhibited, which is beneficial for subsequent processing technology. The result provides a theoretical basis for the intelligent control of glutinous sorghum brewing.

Effect of dynamic high-pressure treatments on the multi-level structure of starch macromolecule and their techno-functional properties: A review

Over the past decades, dynamic high-pressure treatment (DHPT) executed by high-pressure homogenization (HPH) or microfluidization (DHPM) technology has received humongous research attention for starch macromolecule modification. However, the studies on starch multi-level structure alterations by DHPT have received inadequate attention. Furthermore, no review comprehensively covers all aspects of DHPT, explicitly addressing the combined effects of both technologies (HPH or DHPM) on starch's structural and functional characteristics. Hence, this review focused on recent advancements concerning the influences of DHPT on the starch multi-level structure and techno-functional properties. Intense mechanical actions induced by DHPT, such as high shear and impact forces, hydrodynamic cavitation, instantaneous pressure drops, and turbulence, altered the multi-level structure of starch for a short duration. The DHPT reduces the starch molecular weight and degree of branching, destroys short-range ordered and long-range crystalline structure, and degrades lamellar structure, resulting in partial gelatinization of starch granules. These structural changes influenced their techno-functional properties like swelling power and solubility, freeze-thaw stability, emulsifying properties, retrogradation rate, thermal properties, rheological and pasting, and digestibility. Processing conditions such as pressure level, the number of passes, inlet temperature, chamber geometry used, starch types, and their concentration may influence the above changes. Moreover, dynamic high-pressure treatment could form starch-fatty acids/polyphenol complexes. Finally, we discuss the food system applications of DHPT-treated starches and flours, and some limitations.

Effects of Grinding Methods of Tartary Buckwheat Leaf Powder on the Characteristics and Micromorphology of Wheat Dough

The functional components in tartary buckwheat leaf powder can give flour products higher nutritional value. To comprehensively realize the high-value utilization of tartary buckwheat and its by-products, electric stone mill powder (EMP), ultra-fine mill powder (UMP), steel mill powder (SMP), and grain mill powder (GMP) from tartary buckwheat leaves were used in the preparation of wheat dough, and this was used to explore their effects on dough properties and protein microstructure. With an increase in tartary buckwheat leaf powder, the hydration characteristics, protein weakening rate, and starch gelatinization characteristics of the dough changed, and the water holding capacity and swelling capacity decreased. The retrogradation value increased, which could prolong the shelf life of related products. The water solubility of the dough showed an upward trend and was the lowest at 10% UMP. The addition of UMP produced a more uniform dough stability time and the lowest degree of protein weakening, which made the dough more resistant to kneading. An increasing amount of tartary buckwheat leaf powder augmented the free sulfhydryl content of the dough and decreased the disulfide bond content. The disulfide bond content of the dough containing UMP was higher than that of the other doughs, and the stability of the dough was better. The peaks of the infrared spectrum of the dough changed after adding 10% UMP and 20% EMP. The content of α-helical structures was the highest at 10% UMP, and the content of ordered structures was enhanced. The polymerization of low molecular weight proteins to form macromolecular polymers led to a reduction in surface hydrophobic regions and the aggregation of hydrophobic groups. The SEM results also demonstrated that at 10% tartary buckwheat leaf powder, the addition of UMP was significantly different from that of the other three leaf powders, and at 20%, the addition of EMP substantially altered the structure of the dough proteins. Considering the effects of different milling methods and different added amounts of tartary buckwheat leaf powder on various characteristics of dough, 10% UMP is the most suitable amount to add to the dough.

Interaction of the extracellular protease from Staphylococcus xylosus with meat proteins elucidated via spectroscopic and molecular docking

This study aimed to assess the effect of an external protease secreted by Staphylococcus (S.) xylosus on the hydrolysis and flavor properties of meat protein. The results indicated that the protease significantly increased the solubility of myofibrillar proteins (MPs) and sarcoplasmic proteins (SPs) in water (P < 0.05), and altered their surface hydrophobicity and secondary structure. The results of micromorphological and free amino acids analyses suggested that the protease degraded the large and insoluble meat protein aggregates into small molecular proteins with uniform distribution and amino acids, especially glycine, glutamic acid, leucine, and cysteine. Moreover, the protease-catalyzed hydrolysis promoted the formation of some volatile compounds in the MPs and SPs. Additionally, molecular docking analysis suggested that hydrogen bond and hydrophobic interaction promoted the formation of a S. xylosus protease/meat protein complex. These results provided a basis for the future application of S. xylosus protease in meat products.

Gardenia yellow pigment: Extraction methods, biological activities, current trends, and future prospects

Food coloring plays a vital role in influencing consumers' food choices, imparting vibrant and appealing colors to various food and beverage products. Synthetic food colorants have been the most commonly used coloring agents in the food industry. However, concerns about potential health issues related to synthetic colorants, coupled with increasing consumer demands for food safety and health, have led food manufacturers to explore natural alternatives. Natural pigments not only offer a wide range of colors to food products but also exhibit beneficial bioactive properties. Gardenia yellow pigment is a water-soluble natural pigment with various biological activities, widely present in gardenia fruits. Therefore, this paper aims to delve into Gardenia Yellow Pigment, highlighting its significance as a food colorant. Firstly, a thorough understanding and exploration of various methods for obtaining gardenia yellow pigment. Subsequently, the potential functionality of gardenia yellow pigment was elaborated, especially its excellent antioxidant and neuroprotective properties. Finally, the widespread application trend of gardenia yellow pigment in the food industry was explored, as well as the challenges faced by the future development of gardenia yellow pigment in the field of food and health. Some feasible solutions were proposed, providing valuable references and insights for researchers, food industry professionals, and policy makers.

Effects of Wheat Oligopeptide on the Baking and Retrogradation Properties of Bread Rolls: Evaluation of Crumb Hardness, Moisture Content, and Starch Crystallization

Delaying the deterioration of bakery goods is necessary in the food industry. The objective of this study was to determine the effects of wheat oligopeptide (WOP) on the qualities of bread rolls. The effects of WOP on the baking properties, moisture content, and starch crystallization of rolls during the storage process were investigated in this study. The results showed that WOP effectively improved the degree of gluten cross-linking, thereby improving the specific volume and the internal structure of rolls. The FTIR and XRD results showed that the addition of WOP hindered the formation of the starch double helix structure and decreased its relative crystallinity. The DSC results revealed a decrease in the enthalpy change (ΔH) from 0.812 to 0.608 J/g after 7 days of storage with 1.0% WOP addition, further indicating that WOP reduced the availability of water for crystal lattice formation and hindered the rearrangement of starch molecules. The addition of WOP also improved the microstructure of the rolls that were observed using SEM analysis. In summary, WOP is expected to be an effective natural additive to inhibit starch staling and provide new insights into starchy food products.

Research on corn starch and black bean protein isolate interactions during gelatinization and their effects on physicochemical properties of the blends

The interaction between starch and protein during food processing is crucial for controlling food quality. This study aims to understand the interactions between corn starch and black bean protein isolate (BBPI) at various gelatinization phases and their effects on the physicochemical properties of the blends. BBPI reduced the rheological properties of the corn starch/BBPI mixed system during gelatinization, increasing light transmittance and gelatinization temperature, while decreasing total viscosity and enthalpy change. The changes in starch and protein microstructure during gelatinization indicated that BBPI adhered to the starch particle surface or partially penetrated the swollen starch particles. Fourier transform infrared spectroscopy (FT-IR) revealed that BBPI decreased the number of hydrogen bonds within starch, with no newly formed functional groups in the mixed system. Furthermore, BBPI reduced the composite relative crystallinity (RC). The effect of protein addition on water migration in the mixed system demonstrates that protein and starch compete for water during gelatinization, preventing water molecules from diffusing into starch particles.

Investigation of 3D printing of toddler foods with special shape and function based on fenugreek gum and flaxseed protein

The practicability of using corn and flaxseed protein as printing inks for manufacture of printed products specifically designed for toddlers as a dysphagia diet with high precision and special shapes with addition of fenugreek gum (FGG) was investigated. 3D printing was used to process grains and dysphagia-compatible food (corn) into a dietary product with attractive appearance which was also easy to swallow. Rheological measurements shown that appropriate amount of flaxseed protein (FP, 0-10 %) can reduce the stickiness and yield strength of printing material. Based on FTIR measurements, FP weakened the hydrogen bond strength of inks, but it was still an important gradient for the formation of the ink suitable for precision 3D printing. The TPA results shown that the addition of FP (0-10 %) remarkably reduced both the stickiness and hardness of the ink. These results shown that compared with the control group, materials with FGG additions possessed higher printing accuracy and self-supporting ability. Ink with 5 % FP content exhibited the best printability and swallowability, while ink with 10 % FP content had the lowest viscosity and hardness, but it was not suitable for 3D printing. 3D printing of objects printed using Ink-C (5%FP and 0.8 %FGG) showed high support characteristic and attractive appearance. According to the international IDDSI testing standards, Ink-C (5%FP and 0.8 %FGG), Ink-E (15%FP and 0.8 %FGG), and Ink-F (20%FP and 0.8 %FGG) were defined as level 5-minced and moist foods.

Effects of maltodextrin and protein hydrolysate extracted from lotus seed peel powder on the fat substitution and lipid oxidation of lotus seed paste

The fat substitution of maltodextrin from lotus seed peel powder (LSP-MD) and the lipid oxidation inhibitory effect of protein hydrolysate (LSP-PH) on lotus seed paste were investigated in this study. The LSP-MD with a dextrose equivalent value of 2.28 showed the smallest specific volume, strongest water-holding capacity and retrogradation. This LSP-MD effectively maintained the sensory quality, hardness and elasticity of low-fat lotus seed paste during storage at 25 °C. For protein hydrolysate, LSP-PH with a hydrolyzation degree of 13.45 % had the strongest DPPH· scavenging capacity and ferric reducing antioxidant power, which was further confirmed by FTIR spectra that enzymatic hydrolysis of LSP protein could facilitate the transformation of β-sheet into β-turn. Following 15 days of storage, supplementation with 0.5 % LSP-PH reduced the peroxide value and acid value of lotus seed paste, suggesting its excellent inhibitory effect on lipid peroxidation via interacting with hydrophobic polyunsaturated fatty acids.

Enrichment of resistant starch in starch-protein hydrolysate binary matrix by modulating pH during thermal processing

Controlling the digestion features of starch-based food matrices following thermal processing plays vital roles in reducing risks of metabolic diseases such as obesity and type II diabetes. To date, it remains largely unclear how regulating the pH during thermal processing alters the microstructure and digestion features of starch-based matrix including protein hydrolysates. Considering this, corn starch (CS) and soybean protein isolate (SPI) (or its hydrolysates (SPIH)) were used to prepare thermally-processed CS-SPI and CS-SPIH binary matrices under different pH values (3 to 9), followed by inspection of changes in the structures and digestibility using combined methods. It was found that including SPI (especially SPIH) caused structural changes of those binary systems, such as reduced network sizes, increased V-crystals and reduced nanoscale structures, which could allow more resistant starch (RS). This phenomenon was especially true when including SPIH with regulated pH value. For instance, SPIH inclusion at pH 5 caused the highest RS content (about 20.30%), presumably linked to the reduced molecule size of SPIH with strengthened aggregation at pH 5. In contrast, the acidic (pH 3) and alkaline (pH 9) conditions allowed reduced short-range orders and tailored porous networks and thus less RS (ca. 17.46% at pH 3 and 16.74% at pH 9).

Retrogradation inhibition of wheat starch with wheat oligopeptides

Starch staling greatly reduces the cereal products quality, and the staling retardation becomes a focus in current research. The effect of wheat oligopeptide (WOP) on anti-staling properties of wheat starch (WS) was studied. Rheology property indicated that WOP reduced WS viscosity, showing more liquid-like behavior. WOP improved the water holding capacity, inhibited swelling power, and reduced the hardness of WS gels, which decreased from 1200 gf to 800 gf compared with the control after 30 days storage. Meanwhile, the water migration of WS gels were also reduced with WOP incorporation. The relative crystallinity of WS gel with 1% WOP was reduced by 13.3%, and the pore size and the microstructure of gels was improved with WOP. Besides, the short-range order degree reached the lowest value with 1% WOP. In conclusion, this study explained the interaction between WOP and WS, which was beneficial to the application of WOP in WS-based food.

Effect of soluble soybean polysaccharides on the short- and long-term retrogradation properties of instant rice

BACKGROUND

Rice starch retrogradation is prone to occur during instant rice storage, which contributes to reduced viscosity, poor sensory characteristics, and shortened shelf life. The purpose of this study was to explore the anti-retrogradation effect of soybean soluble polysaccharides (SSPS) on instant rice and the possible interaction between SSPS and high-moisture starch products.

RESULTS

We studied the effects of SSPS on the retrogradation of instant rice, using hardness as an index. The optimal amount of SSPS was 0.2%. Hardness, enthalpy, relative crystallinity, and full width at half maximum values were lower in the SSPS-treated group than in the control group (no SSPS) during storage. The weight loss rate of instant rice had the following trend: SSPS-treated group (0 day) < control group (0 day) < SSPS-treated group (28 days) < control group (28 days). The lower the weight loss rate, the lower was the material loss. Scanning electron microscopy results showed that the gaps between starch granules were less obvious in the control group than in the SSPS-treated group during storage. The SSPS-treated group presented a starch network with uniform chambers. SSPS might compete with starch molecules for water absorption, thereby improving water retention and limiting starch retrogradation.

CONCLUSION

The results showed that adding SSPS to instant rice could effectively inhibit starch retrogradation, because the interaction of SSPS and amylopectin side chains inhibited the crosslinking of starch molecules through hydrogen bonds, which hindered the formation of ordered structures. It was helpful to understand the anti-retrogradation mechanism of SSPS during the storage of instant rice, and provided the basis for the industrial production of high-water-content starch foods. © 2023 Society of Chemical Industry.

Effect of rice protein on the gelatinization and retrogradation properties of rice starch

In this study, rice starch (RS) was mixed with varying amounts of rice protein (RP; 0 % to 16 %) to explore the effects of protein on the gelatinization and retrogradation of starch during storage. The increased RP addition decreased the viscosity and gelatinization enthalpy of the mixtures but caused an upward trend in the gelatinization temperature, indicating that protein hampers the process of starch gelatinization. Furthermore, RP addition reduced gel hardness, decreased retrogradation enthalpy and crystallization rate constant, but increased Avrami exponent upon RS retrogradation. RP addition also facilitated the mobility of water molecules, weakened the conversion from bound water to free water in the gels, and moderately increased the uniformity and thickness of gel shape. In summary, RP had a dose-dependent effect on the gelatinization and retrogradation behavior of RS, although the anti-retrogradation concentration effect strongly weakened at protein levels exceeding 12 %. It is noteworthy, that excessive RP addition resulted in disulfide bond formation, which increased gel strength and network structure but reduced the ability of RP to facilitate water molecule mobility and restrict water migration, ultimately reducing its anti-retrogradation capability. This phenomenon can be partially attributed to spontaneous protein-protein interaction caused by excessive protein addition, replacing the starch-protein interaction.

Bioactive food-derived peptides for functional nutrition: Effect of fortification, processing and storage on peptide stability and bioactivity within food matrices

New challenges in food production and processing are appearing due to increasing global population and the purpose of achieving a sustainable food system. Bioactive peptides obtained from food proteins can be employed to prevent or pre-treat several diseases such as diabetes, cardiovascular diseases, inflammation, thrombosis, cancer, etc. Research on the bioactivity of protein hydrolysates is very extensive, especially in vitro tests, although there are also tests in animal models and in humans studies designed to verify their efficacy. However, there is very little published literature on the functionality of these protein hydrolysates as an ingredient in food matrices, as well as the effect that thermal or non-thermal processing, and storage may have on the bioactivity of these bioactive peptides. This review aims to summarize the published literature on protein hydrolysates as a functional ingredient including processing, storage and simulated gastrointestinal digestion regarding the bioactivity of these peptides inside food matrices.

Effects of three glutenins extracted in acidic, neutral and alkaline urea solutions on the retrogradation of wheat amylose and amylopectin

Three glutenins (glutenin 1, glutenin 2, and glutenin 2) were extracted in acidic, neutral and alkaline urea solutions respectively. All of the three glutenins are rich in glutamic acid (Glu, >30 %) and proline (Pro, >20 %). Glutenin 1, extracted at pH 5, shows higher contents of hydrophilic amino acids as serine (Ser, 5.25 %), aspartic acid (Asp, 2.99 %), tyrosine (Tyr, 3.11 %), arginine (Arg, 2.09 %) and threonine (Thr, 2.11 %) than the other two glutenins. The retrogradation of three glutenins with amylose/amylopectin indicated that glutenin 1 showed significant inhibition effect on the retrogradation of wheat amylose. The characterizations of amylose retrograded with glutenin 1 by FT-IR, XRD, DSC and solid ¹³C NMR showed that new hydrogen bonds between Glu, Tyr and wheat amylose were formed, which prevented the formation of hydrogen bonds between amylose themselves. Glycosidic bonds between some hydroxyl groups of C6 in wheat amylose and certain hydroxyl groups of Ser and Thr in glutenin with specific chain length were present. The macromolecules with steric hindrance prevented the rearrangement of amylose into regular crystals. The retrogradation of wheat amylose was inhibited in this way. This study provides a key targeting step to control the retrogradation of amylose.

Effects of different storage temperatures and time on frozen storage stability of steamed bread

BACKGROUNDS

This research intended to explore the effects of different frozen storage temperatures and time on the stability of steamed bread. The quality characteristics, moisture content and microstructure of steamed bread were determined after quick-frozen for 30 min at -32 °C and frozen storage at -6, -12, -18, -24 and -30 °C for 1-4 weeks.

RESULTS

When the frozen storage temperature is lower, the moisture content, specific volume, pH and the strong bound water in the steamed bread increase, the water loss rate and the contents of freezable water, the weak bound water and free water decreased. With the extension of frozen storage time, the pH value and water loss of steamed bread first increased and then decreased, while the trend of water content was opposite. The specific volume, cohesion and elasticity of steamed bread decreased, while the freezable water content, hardness and chewiness increased. The bound water of steamed bread gradually migrated to free water. In addition, the longer the frozen storage time and the higher the temperature, and the more serious the damage to the microstructure was.

CONCLUSION

The shelf life of steamed bread frozen storage at -12 °C could be up to 3 weeks, and the quality of steamed bread stored at -30 °C for more than 3 weeks was the best. © 2022 Society of Chemical Industry.

Incorporating Portulaca oleracea extract endows the chitosan-starch film with antioxidant capacity for chilled meat preservation

This study aimed to investigate the application potential of Portulaca oleracea extract (POE) in active packaging for the preservation of chilled meat. First, the antioxidant capacity and active ingredients of POE were systematically studied. The results demonstrated that POE has excellent antioxidant capacity and contains abundant antioxidant compounds. Subsequently, antioxidant-active packaging films based on chitosan and starch containing different concentrations of POE (CS/POE films) were successfully developed. The main physicochemical and mechanical properties of the CS/POE films were characterized and evaluated. The CS/POE films exhibited remarkable antioxidant activity and can significantly reduce lipid oxidation in meat. Compared with polyethylene film, the CS/POE films-treated meats had better preservation effects and longer shelf-life. These findings suggested that CS/POE film has the potential to become a good alternative to conventional plastics in food packaging. In conclusion, Portulaca oleracea extract is an excellent natural antioxidant with great potential in active packaging for chilled meat preservation.

Effects of drying methods on bioactive components of Ganoderma lucidum fermented whole wheat in products & in vitro digestive model

The content of bioactive components is the key to determining the quality of Ganoderma lucidum fermented whole wheat (GW) products, and drying is a necessary link in the initial processing of GW, which will affect the bioactivity and quality of GW. This paper was to assess the effect of hot air drying (AD), freeze drying (FD), vacuum drying (VD) and microwave drying (MVD) on the content of bioactive substances and the characteristics of digestion and absorption of GW. The results showed that FD, VD and AD were beneficial to the retention of unstable substances such as adenosine, polysaccharide and triterpenoid active components in GW, and their contents were 3.84-4.66 times, 2.36-2.83 times and 1.15-1.22 times of MVD, respectively. The bioactive substances in GW were released during digestion. The bioavailability of polysaccharides in the MVD group (419.91 %) was significantly higher than that in the FD, VD and AD groups (68.74 %-78.92 %), but their bioaccessibility (5.66 %) was lower than that in the FD, VD and AD groups (33.41 %-49.69 %). Principal component analysis (PCA) showed that VD is more suitable for GW drying due to the comprehensive performance of 3 aspects in terms of active substance retention, bioavailability and sensory quality.

Modulation of the self-assembly kinetics and digestibility of type 3 resistant starch particles by co-crystallization with amino acid

The effect of eight different l-amino acids (L-AA) on type-3 resistant starch particles (rSPs) derived from short chain glucan (SCG) was investigated. The L-AA were categorized based on their charge and polarity. The results reveal that positively charged L-AA, such as lysine and arginine, decreased the nucleation and growth rate of rSPs, while non-charged L-AA have negligible effects. Negatively charged L-AA, such as glutamic acid and aspartic acid, had a significant impact on the morphology and crystallinity of the rSPs, resulting in particle size of around 3 μm and crystallinity of around 35%. This implies that charged L-AA influence the arrangement of SCG double helices in the particles. Furthermore, the complexation of SCG with charged L-AA reduced the level of RS in rSPs, indicating that L-AA could be useful in modulating the physical properties and digestibility of rSPs.

Insight into the effect of garlic peptides on the physicochemical and anti-staling properties of wheat starch

The staling of wheat starch in storage seriously damages the quality of starch-based foods, and how to delay the staling has become a topic focus. To solve the problem, this study analyzed the effect of garlic peptides on the physical and retrogradation behaviors of wheat starch during storage. The rheological, pasting, swelling properties, molecular order, water migration, and microstructure of wheat starch gels were evaluated. Our results showed that garlic peptides effectively reduced the storage and loss modulus of wheat starch. The physical properties indicated that garlic peptides suppressed the swelling and gelatinization of starch, which exhibited higher water holding capacity and lower water migration. In addition, garlic peptides incorporated wheat starch exhibited the lowest gel hardness during storage. X-ray diffraction and Fourier Transform Infrared Spectroscopy analysis indicated that garlic peptides could reduce the crystallinity and inhibit the formation of ordered structures in wheat starch gel. The microstructure observation showed that the gel with garlic peptides maintained the integrity of the network structure. Consequently, garlic peptides are expected to be an effective natural additive to inhibit starch staling and provide new insights for starch-based foods.

pH-shifting alters textural, thermal, and microstructural properties of mung bean starch-flaxseed protein composite gels

The objective of this study was to investigate the effect of pH-shifting on the textural and microstructural properties of mung bean starch (MBS)-flaxseed protein (FP) composite gels. Results showed that different pH-shifting treatments caused changes in hydrogen bond interactions and secondary structures in composite gels, leading to the formation of loose or compact gel networks. The pH 2-shifting modified protein and starch molecules with shorter chains tended to form smaller intermolecular aggregates, resulting in the formation of a looser gel network. For pH 12-shifting treatment, conformational change of FP caused the unfolding of protein and the exposure of more hydrophobic groups, which enhanced the hydrogen bond and hydrophobic interactions between polymers, contributing to the formation of a compact gel network. Furthermore, pH 12-shifting improved the water-holding capacity (WHC), storage modulus, and strength of gels, while pH 2-treated gels exhibited lower WHC, hardness, and gumminess due to the degradation of MBS and denaturation of FP caused by extreme acid condition. These findings suggest that pH-shifting can alter the gel properties of bi-polymeric starch-protein composite systems by affecting the secondary structures of proteins and the hydrogen bonding between the polymers, and provide a promising way for a wide application of FP in soft gel-type food production.

Industrial Application of Protein Hydrolysates in Food

Protein hydrolysates, which may be produced by the protein in the middle of the process or added as an ingredient, are part of the food formula. In food, protein hydrolysates are found in many forms, which can regulate the texture and functionality of food, including emulsifying properties, foaming properties, and gelation. Therefore, the relationship between the physicochemical and structural characteristics of protein hydrolysates and their functional characteristics is of significant importance. In recent years, researchers have conducted many studies on the role of protein hydrolysates in food processing. This Review explains the relationship between the structure and function of protein hydrolysates, and their interaction with the main ingredients of food, to provide reference for their development and further research.

The Effect of Different Ratios of Starch and Freeze-Thaw Treatment on the Properties of Konjac Glucomannan Gels

The composite gels of konjac glucomannan (KGM) and corn starch (CS) were prepared and treated by the freeze-thaw method. For KGM-CS gels, as the starch ratio rose from 0 to 100%, storage modulus (G') decreased by 97.7% (from 3875.69 Pa to 87.72 Pa), degradation temperature decreased from 313.32 °C to 293.95 °C, and crystallinity decreased by 16.7%. For F-KGM-CS gels, G' decreased by 99.0% (from 20,568.10 Pa to 204.09 Pa), degradation temperature increased from 289.68 °C to 298.07 °C, and crystallinity decreased by 17.1% with more starch content. The peak in infrared spectroscopy shifted to a higher wavenumber with more starch and to a lower wavenumber by freezing the corresponding composite gels. The detected retrogradation of the composite gels appeared for KGM-CS with 80% starch and F-KGM-CS with 40% starch. The endothermic enthalpy of free water rose by 10.6% and 10.1% with the increase in starch for KGM-CS and F-KGM-CS, respectively. The results of moisture distribution found that bound water migrated to free water and the water-binding capacity reduced with more starch. The results demonstrated that the molecular interaction in composite gels was weakened by starch and strengthened by freezing.

Interaction between Kidney-Bean Polysaccharides and Duck Myofibrillar Protein as Affected by Ultrasonication: Effects on Gel Properties and Structure

The interaction of polysaccharides-protein with varied origins and structures provides opportunities for tailoring the physicochemical qualities of food protein-based materials. This work examined the feasibility of ultrasound-modified interaction between kidney bean dietary fiber (KSDF) and duck myofibrillar proteins (MP) to improve the physicochemical properties of the gel matrices. Accordingly, gel strength, water holding capacity, solubility, chemical interaction, secondary structure, and network structure of MP were determined. The addition of KSDF combined with the ultrasound treatment contributed to the improved water retention capability, G' values, and the reduced particle size of protein molecules, corresponding with the formation of dense pore-like structures. The results demonstrated that 1% KSDF and ultrasonication at 400 W significantly enhanced gel strength by up to 109.58% and the solubility increased by 213.42%. The proportion of α-helices of MP gels treated with 1% KSDF and ultrasonication at 400 W was significantly increased. The sonication-mediated KSDF-MP interaction significantly improved hydrophobic interactions of the proteins, thus explaining the denser network structure of the MP gels incorporated KSDF with ultrasound treatments. These results demonstrated the role of ultrasonication treatments in modifying KSDF-protein interaction to improve the gel and structural properties of the MP gels.

Interaction between protease from Staphylococcus epidermidis and pork myofibrillar protein: Flavor and molecular simulation

This study investigated the influence of a protease from Staphylococcus (S.) epidermidis on the hydrolysis and flavor development in pork myofibrillar protein (MP). The surface hydrophobicity, fluorescence, Fourier transform infrared spectra, and atomic force microscopy analysis indicated that hydrolysis significantly changed surface hydrophobicity and secondary structure of MP (p < 0.05), and improved the stability of MP in water. The contents of free amino acid from MP, especially glutamic and alanine, significantly increased (p < 0.05), and the production of volatile compound such as aldehydes, alcohols and acid were promoted under the action of protease. MP treated with S. epidermidis protease is non-cytotoxic to the HEK-293 cells. Molecular docking analysis suggested that the interaction between the protease and actin was spontaneous and mainly involved hydrogen bonding forces. In summary, this study provides a theoretical basis for the future application of S. epidermidis protease in fermented meat products.

Structure-digestibility relationships in the effect of fucoidan on A- and B-wheat starch

Fucoidans (FC) have a variety of biological activities, and it can also affect the functionality and nutritional characteristics of starch-based food products. However, there are few studies on the structural and digestive properties of starch - fucoidans blends. The effect of FC at different concentrations (0, 0.6 %, 0.8 %, 1.0 %, w/v) on the structural properties and digestibility properties of A-type wheat starch (AS) and B-type wheat starch (BS) subjected to autoclave treatment were investigated. The results show that compared with native wheat starch, AS with FC displayed higher crystallinity as well as the structural ordering, but the crystallinity and degree of order of BS with FC decreased, which was proposed due to AS interact with FC in crystalline region but BS reacts with FC in the amorphous region. With the interaction of FC with AS and BS, granules compactness of AS and BS were enhanced. The addition of FC delayed digestion in vitro of AS and BS, the rapidly digestible starch content was obviously lower than native one, and the proportion of slowly digestible starch raise markedly. This study might broaden the recognition of wheat starch with different proportion of AS and BS, and provide a theoretical basis for the potential utilization of FC in carbohydrate based food industry.

Recent application of protein hydrolysates in food texture modification

The demand for clean labels has increased the importance of natural texture modifying ingredients. Proteins are unique compounds that can impart unique textural and structural changes in food. However, lack of solubility and extensive aggregability of proteins have increased the demand for enzymatically hydrolyzed proteins, to impart functional and structural modifications to food products. The review elaborates the recent application of various proteins, protein hydrolysates, and their role in texture modification. The impact of protein hydrolysates interaction with other food macromolecules, the effect of pretreatments, and dependence of various protein functionalities on textural and structural modification of food products with controlled enzymatic hydrolysis are explained in detail. Many researchers have acknowledged the positive effect of enzymatically hydrolyzed proteins on texture modification over natural protein. With enzymatic hydrolysis, various textural properties including foaming, gelling, emulsifying, water holding capacity have been effectively improved. It is evident that each protein is unique and imparts exceptional structural changes to different food products. Thus, selection of protein requires a fundamental understanding of its structure-substrate property relation. For wider applicability in the industrial sector, more studies on interactions at the molecular level, dosage, functionality changes, and sensorial attributes of protein hydrolysates in food systems are required.

Storage Stability of Chilled and Frozen Starch Gels as Affected by Blended Starch Formulation, Sucrose Syrup, and Coconut Milk

Effects of starch formulation, highly concentrated sucrose solution, and coconut milk on the stability of starch gels kept under chilled and frozen conditions were determined. Gels containing rice starch (RS), tapioca starch (TS) (RS:TS of 1 : 0.85), and hydroxypropyl distarch phosphate (HDP, 0-50% of total starch) were prepared from 15% starch suspension using water, 45°Brix sucrose syrup or coconut milk as liquid media. After aging at 4°C for 21 days, starch gels had higher hardness and chewiness, with lower cohesiveness and springiness (p ≤ 0.05). Water-based gels containing HDP had less extent of texture hardening, lower degree of crystallinity, and more homogeneous microstructure during 4°C aging. However, for the starch gels in sucrose syrup or coconut milk, HDP induced greater gel hardening, higher degree of crystallinity, and denser gel microstructure during chilled storage. This could be due to the crystallization of sucrose or lipid/amylose-lipid complexes. Nevertheless, HDP enhanced freeze-thaw stability of the gels, regardless of the liquid media used (p ≤ 0.05). According to the consumer test of the model desserts subjected to a single freeze-thaw cycle, the sample containing 50% HDP gel in sucrose syrup or 25% HDP gel in coconut milk gained the highest hedonic score of texture and overall acceptance (p ≤ 0.05).

Amaranth selective hydrolyzed protein influence on sourdough fermentation and wheat bread quality

Amaranth selective hydrolyzed protein (ASPH) may improve sourdough properties and bread quality. In this regard, this study focused on investigating the influence of protein hydrolysates on sourdough fermentation and bread properties. Based on the findings, ASPH further increased Lactobacillus plantarum and Saccharomyces cerevisiae growth in sourdough compared with amaranth protein isolates and amaranth flour. ASPH at 5 g/kg resulted in sourdough with higher pH and total titratable acidity (TTA) after 20 h of fermentation at 30°C. The prepared sourdough using APH (S-ASPH) at 3 g/kg increased the specific volume (4.57 ml/g) and TTA (4.76 ml) while decreasing water activity, hardness, cohesiveness, and chewiness of the bread (S-ASPH-B) compared with the control. Moreover, transition temperature and enthalpy reduced whereas sensory properties and shelf life represented an increase with S-ASPH addition. Overall, the obtained data indicated the improvement of bread quality by S-ASPH sourdough.

Retardant effect of different charge-carrying amino acids on the long-term retrogradation of normal corn starch gel

The effects of different charge-carrying amino acids (lysine, aspartic acid, and tyrosine) on the long-term retrogradation properties of normal corn starch (NCS) gel were studied by differential scanning calorimetry, X-ray diffractometry, low-field nuclear magnetic resonance, and dynamic rheological tests. The results suggested that these amino acids could inhibit the long-term retrogradation of NCS gels, among which the positively charge-carrying amino acid (lysine) showed the most significant inhibitory effect and the zero net charged amino acid (tyrosine) exhibited the worst inhibitory effect. These amino acids significantly decreased the retrogradation enthalpy, hardness, and R_1047/1022 value of NCS gels, as well as inhibited the recrystallization of NCS. The results of retrogradation kinetics suggested that the recrystallization of NCS with amino acids followed the instantaneous nucleation and the crystallization rate constant k of recrystallization was reduced by these amino acids. The amino acids could interact with starch molecules to form hydrogen bonds and steric hindrance during the recrystallization process, which prevented the formation of double helix structures, as well as reduced the water diffusion and exudation from NCS. Therefore, the lysine could be used as a good retrogradation inhibitor for starch in food industry.

Stability evaluation of gardenia yellow pigment in presence of different phenolic compounds

Gardenia yellow pigment (GYP) may undergo chemical degradation under different conditions resulting in color fading. This study investigated the effects of different phenolic compounds (caffeic acid, rosmarinic acid, tannic acid, epicatechin, chlorogenic acid, epigallocatechin, and epigallocatechin gallate) on the physical and chemical stability of GYP under light and different temperatures. Furthermore, food models with GYP/phenolic compounds were simulated to evaluate the GYP stability under different cooking methods. The addition of phenolic compounds, especially tannic acid, epigallocatechin gallate, epigallocatechin, and rosmarinic acid, significantly improved the GYP stability during light and thermal treatments. Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopy confirmed that the formation of hydrogen bonds between GYP and selected phenolic compounds (tannic acid, epigallocatechin gallate, epigallocatechin, and rosmarinic acid), which may lead to the enhancement of GYP stability. Moreover, these selected phenolic compounds provided potent protective effects on GYP under different cooking methods.