Effect of preheating-induced denaturation of proteins and oleosomes on the structure of protein and soymilk properties.

In this paper, effects of preheating-induced denaturation of proteins and oleosomes on protein structure and soymilk quality were studied. The protein in soybeans baked at 55 °C (B-55) and 85 °C (B-85) showed an increase of ß-sheet content by 3.2 % and a decrease of α-helix content by 3.3 %, indicating that proteins were gradually unfolded while oleosomes remained intact. The protein resisted thermal denaturation during secondary heating, and soymilks were stable as reflected by a small d3,2 (0.4 µm). However, raw soymilk from soybeans baked at 115 °C (B-115), steamed for 1 min (ST-1) and 5 min (ST-5) presented oleosomes destruction and lipids aggregates. The proteins were coated around the oil aggregates. The ß-turn content from soybeans steamed for 10 min (ST-10) increased by 9.5 %, with a dense network where the OBs were tightly wrapped, indicating the serious protein denaturation. As a result, the soymilks B-115 or steamed ones were unstable as evidenced by the serious protein aggregation and larger d3,2 (5.65-12.48 µm). Furthermore, the soymilks were graininess and the protein digestion was delayed due to the formation of insoluble protein aggregates. The flavor and early-stage lipid digestion of soymilk from steamed soybeans was improved owing to lipid release.

Enhancing the nonlinear rheological property and digestibility of mung bean flour gels using controlled microwave treatments: Effect of starch debranching and protein denaturation.

In this study, we examined the possibility of using industrial microwave processing to enhance the gelling properties and reduce the starch digestibility of mung bean flour (MBF). MBF (12.6 % moisture) was microwaved at a power of 6 W/g to different final temperatures (100-130 °C), and then its structural and functional properties were characterized. The microwave treatment had little impact on the crystalline structure or amylose content of the starch, but it roughened the starch granule surfaces and decreased the short-range ordered structure and degree of branching. In addition, the extent of mung bean protein denaturation caused by the microwave treatment depended on the final temperature. Slightly denaturing the proteins (100 °C) did not affect the nature of the gels (protein phase dispersed in a starch phase) but the gel network became more compact. Moderately denaturing the proteins (110-120 °C) led to more compact and homogeneous starch-protein double network gels. Excessive protein denaturation (130 °C) caused the gel structure to become more heterogeneous. As a result, the facilitated tangles between starch chains by more linear starch molecules after debranching, and the protein network produced by moderate protein denaturation led to the formation of stronger gel and the improvement of plasticity during large deformation (large amplitude oscillatory shear-LAOS). Starch recrystallization, lipid complexion, and protein network retard starch digestion in the MBF gels. In conclusion, an industrial microwave treatment improved the gelling and digestive properties of MBF, and Lissajous curve has good adaptability in characterizing the viscoelasticity of gels under large deformations.

Risk factors and healing factors for pharyngocutaneous fistula after total laryngectomy for laryngeal cancer: An epidemiological study.

To analyse the risk factors and healing factors of pharyngocutaneous fistula (PCF) in patients with laryngeal cancer after total laryngectomy, and to explore the relevant epidemiology. A retrospective analysis was conducted on laryngeal cancer patients who underwent total laryngectomy in our hospital from January 2010 to December 2022. The 349 patients included in the study were divided into a PCF group of 79 and a non-PCF group of 270. Perform one-way analysis of variance and multivariate logistic analysis on various data of patients included in the statistics, and analyse the risk factors and healing factors of PCF. Smoking, history of radiation therapy for laryngeal cancer, history of chemotherapy for laryngeal cancer, tumour location (larynx, pharynx, oesophagus), preoperative albumin, postoperative proteinaemia, <99 haemoglobin, postoperative haemoglobin, postoperative C-reactive protein (CRP) level are the risk factors for PCF. Also, radiation therapy and postoperative proteinaemia were the main reasons for preventing PCF healing. Smoking history, laryngeal cancer, radiation therapy, albumin, haemoglobin and CRP are risk factors for postoperative PCF after total laryngectomy, while radiation therapy and postoperative hypoalbuminaemia are key factors affecting PCF healing.

Effects of heat treatment at different moisture of mung bean flour on the structural, gelation and in vitro digestive properties of starch.

Effects of heat treatment (100 °C) at different moisture content (13-70 %) on the structural, gelation and digestive properties of starch in real mung bean flour (MBF) systems are investigated. The results showed that the structural destruction of the starch, the starch-lipid complexion and starch-protein interaction were promoted with increasing moisture content. The starch-protein interaction was mainly driven by hydrophobic interaction forces, leading the increase of total phase transition enthalpy. Even though starch retained ordered structure after heating at 50 %-70 % moisture, the typical pasting curve almost disappeared. The less leached amylose to construct the continuous phase, and more flexible amylopectin swollen granules dispersed in the matrix may weakened the viscoelasticity of the gels. As a result, two distinct gel textures were presented: soft solids with good water-binding capacity (below 30 %) and pasty fluids (above 40 %). Starch-lipid/protein interactions were demonstrated to retard the digestion rate of starch during MBS gelatinization according to the two-stage first-order kinetic and LOS (logarithm of the slope) models.

Effects of apple fiber on the physicochemical properties and baking quality of frozen dough during frozen storage.

The effects of apple fiber on gluten structure and corresponding frozen dough quality during frozen storage were studied. The addition of 0.50% and 0.75% apple fiber effectively preserved gluten structure by inhibiting the breakage of disulfide bonds and promoting the formation of hydrogen bonds. Notably, the presence of 0.75% apple fiber increased the ß-turn of gluten from 29.60% to 33.84%. Fiber-enriched frozen dough exhibited a smoother and more compact microstructure, but excessive fiber addition (more than 1.00%) had adverse effects. The freezable water content of frozen dough decreased as fiber addition increased. Correspondingly, the addition of 1.50% apple fiber resulted in a 56.08% increase in storage modulus, indicating improved viscoelasticity of the dough. Consequently, the addition of 0.50% and 0.75% apple fiber alleviated the quality deterioration of frozen dough bread in terms of larger specific volume, softer and more uniform crumb.

Effect of stearic and oleic acid-based lipophilic emulsifiers on the crystallization of the fat blend and the stability of whipped cream.

Effect of stearic acid-based lipophilic emulsifiers (sorbitan monostearate (Span-60), sucrose ester S-170, and lactic acid esters of monoglycerides (LACTEM)) and oleic acid-based lipophilic emulsifiers (sorbitan monooleate (Span-80) and sucrose ester O-170) on the crystallization of fat blend and the stability of whipped cream were studied. Span-60 and S-170 possessed strong nucleation inducing ability and good emulsifying properties. Thus, tiny and uniform crystals were formed in fat blends, small and ordered fat globules were distributed in emulsions, and air bubbles were effectively wrapped in firmly foam structures. The crystallization of the fat blend and the stability of whipped cream were slightly modified by LACTEM due to its poor nucleation inducing ability and moderate emulsifying characteristic. Span-80 and O-170 had weak nucleation inducing ability and poor emulsifying properties, therefore, loose crystals were formed in fat blends and some big fat globules were separated in emulsions, thereby decreasing the stability of whipped creams.

Formation, texture, and stability of yolk-free mayonnaise: Effect of soy peptide aggregates concentration.

A kind of yolk-free mayonnaise (YFM) with preferable quality was prepared by insoluble soy peptide aggregates (ISPA) in present work. The basic properties, rheology, texture, sensory quality, and stability for YFM with different concentration of ISPA were explored. As ISPA concentration increased from 1.50 wt% to 3.00 wt%, the droplet size of YFM decreased by 5.35 µm, while the storage and loss modulus increased 2.02 and 1.99 times, moreover, the thixotropic recovery percentage, hardness and gumminess of YFM increased to 95.84 %, 13.29 g and 10.05, respectively. Meanwhile, the ISPA concentration had positive effect on the oxidation stability and thermal stability for YFM. Noticeably, YFM with 2.75 wt% ISPA had good textural properties and sensory quality, which were close to those of commercial mayonnaise. In conclusion, YFM prepared by ISPA had low cholesterol level, which provided a new strategy for solving the health problems of traditional mayonnaise.

Effects of Glucose and Corn Syrup on the Physical Characteristics and Whipping Properties of Vegetable-Fat Based Whipped Creams.

The aim of this work is to evaluate the effects of glucose and corn syrup on the physical characteristics and whipping properties of whipped creams. The interfacial protein concentration and apparent viscosity of emulsions increased with an increasing sugar concentration. In whipped creams, a shorter optimum whipping time (top), higher fat coalescence degree, higher firmness and higher stability were detected as sugar concentration increased. The partial coalescence degree, overrun and firmness of whipped cream with 30 wt% glucose reached 76.49%, 306% and 3.82 N, respectively, significantly (p < 0.05) higher than those (67.15%, 235% and 3.19 N) with 30 wt% corn syrup. Compared with glucose at the same sugar concentration, higher interfacial protein concentration and less-shaped aggregates and coalescences were observed for the emulsions upon the addition of corn syrup, which caused a lower degree of fat coalescence and a lower firmness of whipped cream. The differences could be explained by the presence of maltodextrin (MDX) in corn syrup, which protects absorbed protein throughout freezing and retards the formation of a continuous network during whipping. As a result, the addition of sugars could well improve stability of emulsion, firmness and foam stability of whipped cream efficiently. With a 25−30 wt% sugar addition, even if there was a lower partial coalescence degree and firmness compared with glucose, whipped cream with corn syrup exhibited relatively good stability. These results suggest that MDX improves the stability of emulsion and, thus, has a potential use in low-sugar whipped cream.

Formation and stability of Pickering emulsion gels by insoluble soy peptide aggregates through hydrophobic modification.

In this work, a highly stable food-grade Pickering emulsion gels was successfully prepared by hydrophobically modified insoluble soybean peptide aggregates. The relationships between the surface properties of insoluble soybean peptide aggregates and Pickering emulsion gels characteristics were clarified. After modification, the insoluble soybean peptide aggregates with high surface hydrophobicity had small particle size (377 nm), near-neutral wettability (θo/w = 92°) and strong interfacial adsorption capability. These allowed the modified insoluble soybean peptide aggregates to stabilize the oil-water interface and form continuous network surrounding oil droplets, leading to the formation of stable Pickering emulsion gels. Besides, Pickering emulsion gels prepared by insoluble soybean peptide aggregates with higher surface hydrophobicity had smaller droplet size and higher gel strength, and remained stable even after 60 days of storage. The findings suggest a preferable plant protein particle for the preparation of stable Pickering emulsion gels in food industry.

Whipping properties and stability of whipping cream: The impact of fatty acid composition and crystallization properties.

In this study, five fats (hydrogenated palm kernel oil, HPKO-A and HPKO-B; refined vegetable oils, RVO-A and RVO-B; transesterification oil, TO) were used to prepare whipping creams. HPKO-A and RVO-A which rich in lauric and myristic acids facilitated the formation of small crystals and dense crystal network, while higher stearic acid content of HPKO-B formed large spherical crystals. The richness in palmitic acid (RVO-B and TO) and oleic acid (TO) led to the formation of weak crystal network. Higher partial coalescence was correlated to higher collision frequency of fat globules and crystal connection, therefore, the overruns, firmness and stability of creams prepared by HPKO-A and RVO-A were higher than those of HPKO-B and RVO-B. The least stability of cream prepared by TO was related to the weak crystal networks. In summary, higher lauric and myristic acids content resulted in dense crystal networks, promoting partial coalescence and improving the cream quality.

Molecular Mechanism for Improving Emulsification Efficiency of Soy Glycinin by Glycation with Soy Soluble Polysaccharide.

Glycation with carbohydrates has been considered to be an effective strategy to improve the emulsifying properties of plant storage globulins, but the knowledge is inconsistent and even contradictory. This work reported that the glycation with soy soluble polysaccharide (SSPS) progressively improved the emulsification efficiency of soy glycinin (SG) in a degree-of-glycation (DG)-dependent manner. The glycation occurred in both the acidic (A) and basic (B) polypeptides to a similar extent. The physicochemical and structural properties of glycated SG samples with different DG values of 0-35% were characterized. The emulsifying properties of unglycated and glycated SG were performed on the emulsions at an oil fraction of 0.3 and a protein concentration in the aqueous phase, produced using microfluidization as the emusification process. The glycation with increasing the DG led to a progressive decrease in solubility and surface hydrophobicity but remarkably increased the magnitude of ζ-potential. Dynamic latter scattering and spectroscopic results showed that the glycation resulted in a gradual dissociation of the 11S-form SG at the quaternary level (into different [AB] subunits), in a DG-dependent way, while their tertiary ([AB] subunits) and secondary structure were slightly affected. Besides the emulsification efficiency, the glycation progressively accelerated the droplet flocculation and facilitated the adsorption of the proteins at the interface and formation of bridged emulsions. The results demonstrated that the improvement of the emulsification efficiency of SG by the glycation with SSPS was largely attributed to the enhanced conformation flexibility at the [AB] subunit level as well as facilitated formation of bridged emulsions. It was also confirmed that once the glycated SG adsorbed at the interface, it would readily dissociated into subunits; the dissociated [AB] subunits exhibited an outstanding Pickering stabilization. The findings would be of importance for providing new knowledge about the molecular mechanism for the modification of emulsifying properties of oligomeric globulins by the glycation with polysaccharides.

Ovalbumin as an Outstanding Pickering Nanostabilizer for High Internal Phase Emulsions.

There is still a debate about the effectiveness of native globular proteins to perform as Pickering-like stabilizers for oil-in-water high internal phase emulsions (HIPEs). In the work, we report one native globular protein (ovalbumin) with strong structural integrity and high refolding ability, exhibits an outstanding Pickering stabilization for HIPEs. Ultrastable gel-like HIPEs can be formed through a facile one-pot homogenization even at a concentration as low as 0.2 wt %. The HIPEs formed in the protein-poor regime are a kind of self-supporting and remoldable hydrogel consisting of bridging droplets. The formed HIPEs also exhibit other unique characteristics, such as extraordinary coalescence stability (against prolonged storage or heating), susceptibility to freeze-thawing, enhanced oxidation stability (to encapsulated bioactives), and inhibited vaporization of volatile oils. The findings would be of importance for extending the HIPEs to be applied in food, cosmetic, and petroleum industries.