Impacts of soybean protein isolate hydrolysates produced at high hydrostatic pressure on gelling properties, structural characteristics, and molecular forces of myofibrillar protein.

BACKGROUND: Soybean protein isolate hydrolysates (SPIHs) produced at high hydrostatic pressure have higher bioactivity. The aim of the study was to analyze the effects of different SPIH concentrations obtained under various pressures (0.1, 100, 200, and 300 MPa) on gelling properties, structural characteristics, and main forces of myofibrillar protein (MP) in MP-SPIH plural gels. RESULTS: The MP-SPIH plural gel with 3% SPIH produced under 200 MPa had the maximum gel strength (0.42 N) and water holding capacity (53.69%). A decline in thermal stability and a rise in storage modulus (G') of MP-SPIH plural gels were found with increased SPIH pressure and concentration. Additionally, the addition of SPIHs increased the amounts of α-helix and ß-sheet, decreased random coil structural content of MP in MP-SPIH plural gels, and facilitated the generation of a denser and uniform gels network. The molecular forces in MP-SPIH plural gels were mainly hydrophobic interaction and hydrogen bond. CONCLUSION: This study showed that the interaction of MP with 3% SPIH obtained at 200 MPa improved the quality of plural gels. © 2022 Society of Chemical Industry.

Effects of quercetin on the gel properties of pork myofibrillar proteins and related changes in protein conformation.

BACKGROUND: To study the effects of quercetin on the functionality of myofibrillar proteins (MPs), various levels of quercetin (0, 10, 50, 100 and 200 µmol g-1 protein) were added to MP solution and the structure and gel properties of MPs were determined. RESULTS: Compared with the control MPs not treated with quercetin, adding 10, 50 and 100 µmol g-1 quercetin caused a significant (P < 0.05) loss of sulfhydryls; 10 and 50 µmol g-1 quercetin enhanced the surface hydrophobicity significantly (P < 0.05), and 50, 100 and 200 µmol g-1 quercetin reduced the fluorescence intensity of tryptophan. Additions of 50, 100 and 200 µmol g-1 quercetin resulted in a significant (P < 0.05) reduction in MP solubility. Adding 10, 50 and 100 µmol g-1 quercetin did not significantly (P > 0.05) change the gel strength and water-holding ability of MPs than control, but 200 µmol g-1 quercetin declined the gel properties significantly (P < 0.05). The microstructure and dynamic rheological properties confirmed the results of the gel properties of MPs affected by various levels of quercetin. CONCLUSION: The results obtained in the present study show that mildly high levels of quercetin can maintain the gel properties of MPs, which may be a result of the moderate MP cross-linkage and aggregation caused by the covalent and non-covalent interactions of MPs. © 2023 Society of Chemical Industry.

Characteristics and formation mechanism of key volatile compounds in sugar-smoked chicken.

In this paper, the volatile compounds and profile of sugar-smoked chicken thighs were studied, which were proceed by using dividual smoking materials such as sucrose, maltose, glucose, fructose and xylose. A total of 33 volatile compounds in sugar-smoked samples were identified and quantitated by gas chromatography/mass spectrometry (GC/MS). The furfural, 5-methylfurfural, 1-octene-3-ol, hexanal, heptanal and nonanal were the most important volatile compounds with odour activity values (OAVs) greater than 1, among which furfural and 5-methylfurfural contributed mainly to the smoky aroma. The sucrose, glucose and fructose pyrolysis all produced high yield of furans, such as furfural (FF) and 5-hydroxymethylfurfural (5-HMF) based on pyrolysis mass spectrometry and gas chromatography/mass spectrometry (Py-GC/MS). During the smoking process, then the 5-HMF pyrolyzed into 5-methylfurfural. The sucrose was the good carbohydrate to form furans with smoky aroma. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13197-021-05071-y.

In vitro digestion of emulsified lard-based diacylglycerols.

BACKGROUND: Diacylglycerols as a fat substitute in meat products is a growing area of interest. This study was conducted to analyze the digestion rate, digestion extent, and changes in interfacial properties of lard, glycerolized lard (GL), and purified GL (PGL) in an emulsions system by pH-stat in vitro digestion. RESULTS: PGL had significantly higher hydrolysis rate and final digestion extent than lard (P ≤ 0.05) during in vitro digestion. The analysis on diameter variations of lard, GL, and PGL during digestion indicated that the surface- and volume-weighted mean particle diameters of all samples had the same variation trend, but variation degree was different. Concurrently, the ζ-potential analysis of the lard, GL, and PGL during the digestion process showed that the absolute values of the ζ-potentials of the three types of lipids increased at first and subsequently decreased. The microstructure changes results for lard, GL, and PGL showed there was no obvious flocculation, and the particle size of lard throughout the digestion process was larger than that of GL and PGL. CONCLUSION: This study showed that lard-based diacylglycerols had high digestibility characteristics and could be applied as a functional lipid in meat products to improve human health. © 2020 Society of Chemical Industry.

Effect of high-pressure processing enzymatic hydrolysates of soy protein isolate on the emulsifying and oxidative stability of myofibrillar protein-prepared oil-in-water emulsions.

BACKGROUND: Oil-in-water (O/W) emulsions are thermodynamically unstable and are easily oxidized. Recently, protein hydrolysates have been used to enhance the emulsifying and oxidative stability of emulsions. High-pressure processing (HPP) enzymatic hydrolysates of soy protein isolate have higher bioactivities. The objective of the study was to investigate the effects of various soy protein isolate hydrolysate (SPIH) concentrations obtained during different 4 h pressure treatments on improving the emulsifying and oxidative stability of myofibrillar protein (MP) emulsions. RESULTS: Emulsions with 4 mg mL-1 SPIH obtained at 200 MPa had the highest emulsifying activity index and emulsion stability index (P ≤ 0.05). This increase in emulsion stability was related to increased zeta potential and reduced average particle size. Optical microscopy and confocal laser scanning microscopy observations confirmed that emulsions with 4 mg mL-1 SPIH possessed relatively small oil droplets. The addition of SPIH obtained at 200 MPa significantly reduced thiobarbituric acid reactive substance values (P ≤ 0.05) of emulsions during 8 days of storage. Concurrently, the carbonyl content remained the lowest and the sulfhydryl content remained the highest, which indicated that the emulsions had higher protein oxidative stability. CONCLUSIONS: SPIH obtained under HPP could improve the emulsifying and oxidative stability of MP-prepared O/W emulsions.

Impact of oral processing on texture attributes and taste perception.

Mastication is the first step of food digestion, where foods are broken down and simultaneously impregnated by saliva resulting in the formation of semi-fluids known as food boluses. This review focuses on the impact of oral processing on texture attributes and taste perception. The article describes the oral actions in which texture characteristic are measured for the critical conditions that trigger swallowing. Taste perception also plays a key role in oral processing and oral sensations. There are still challenges in terms of determining different oral physiological characteristics. These include individual chewing behavior regardless of the temporal aspects of dominant processes of comminution, insalivation, bolus formation and swallowing. A comprehensive approach is essential to process favorable foods with respect to the food properties of texture and taste.

Flavor profile analysis of grilled lamb seasoned with classic salt, chili pepper, and cumin (Cuminum cyminum) through HS-SPME-GC-MS, HS-GC-IMS, E-nose techniques, and sensory evaluation on Sonit sheep.

In this study, the volatile flavor profiles of grilled lamb seasoned with salt, chili pepper, and cumin were analyzed employing HS-SPME-GC-MS, HS-GC-IMS, E-nose, and sensory evaluation techniques. The E-nose was found effective in differentiating the samples seasoned variously. A total of 67 volatile compounds were identified by HS-SPME-GC-MS, and 59 by HS-GC-IMS. The PCA demonstrated a correlation between the seasonings and the volatile compounds, with five principal components accounting for 99.54% of the total variance. 1-octen-3-ol, 3-furanmethanol, acetic acid, and heptanal were introduced by salt; compounds like propyl acetate were correlated with chili pepper; a broader range, including ethyl 3-methylbutanoate and high concentrations of alpha-pinene, was associated with cumin. Samples seasoned with all three ingredients showed similarities to those associated with cumin, alongside unique compounds such as gamma-octalactone and alpha-pinene. Sensory evaluations by consumers indicated that the combination of these seasonings significantly enhanced the overall acceptability of the grilled lamb. PRACTICAL APPLICATION: Utilizing modern analytical techniques, this study has successfully revealed the distinct impacts of seasonings-salt, chili pepper, and cumin-on the flavor profile of grilled lamb. By providing experimental data on how each seasonings influence the flavor profile of grilled lamb prepared with Sonit sheep. The research offers theoretical foundation for the development of grilled lamb products. By conducting a thorough comparison between GC-MS and GC-IMS, this study has expanded the understanding of the distinct characteristics of these two technologies. It has also provided a clearer analysis of some flavor compounds dimers produced in GC-IMS system.

Effects of different drying methods on physicochemical, textural, flavor, and sensory characteristics of yak jerky.

The work aimed to study the effect of four drying methods, namely constant temperature hot air drying (HD), microwave drying (MD), hot air microwave drying (HMD), and gradient hot air drying (GHD), on quality characteristics of dried yak meat. The analyses of physicochemical, textural, flavor, and sensory characteristics were carried out based on these four drying methods. The results revealed that microwave dried yak jerky exhibited better color and received the highest sensory score. Hardness of samples were affected by the drying methods, which showed significant differences. There were 21 free amino acids (FAAs) detected in dried yak samples. The samples treated by microwave drying showed the highest total free amino acid content (73.30 mg/100 g) and the EUC value was significantly higher than other methods, indicating the sample displayed greater flavor. A total of 153 volatile compounds were identified in dried yak meat samples, primarily including aldehydes, ketones, and esters. Moreover, the sensory evaluation indicated that the drying methods could significantly affect on color, flavor, and overall acceptability of different samples. Microwave drying samples scored higher than other drying methods. Overall, considering aspects of quality, time savings, and energy efficiency, microwave drying of yak jerky emerges as a more satisfactory option. This study could provide important theoretical support for the application of drying methods to improve the quality of yak jerky and enhance production efficiency.

Relationship between phospholipid molecules species and volatile compounds in grilled lambs during the heating process.

The present study used a comprehensive analysis combining headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS) and ultra-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UPLC-ESI-MS/MS) to investigate changes in volatile compounds and phospholipid molecules in grilled lambs. The results revealed 19 key volatile compounds (OAV > 1) involved in the grilling process of lambs. Additionally, UPLC-ESI-MS/MS analysis detected 142 phospholipid molecules in grilled lamb, with phosphatidylcholine exhibiting the highest content (36.62 %), followed by phosphatidyl ethanolamine, phosphatidylinositol, phosphatidylserine, phosphatidyl glycerol, and phosphatidic acid. Through partial least squares analysis, 63 key differential phospholipids were identified. Principal component analysis of the key differential phospholipids and volatile compounds indicated that phosphatidylcholine and phosphatidyl ethanolamine phospholipids are the key substrates in forming volatile compounds in grilled lambs. This information is essential for precisely regulating the flavor profile, enhancing the grilling process, and minimizing the production of harmful compounds in grilled meat products.

Exploring the formation pathway and antioxidant properties of the sugar-smoking pigment 5-GGMF.

The present study aimed to elucidate the pathway of pigment formation and identify the source of antioxidant activity during sugar smoking. Building upon previous research, this investigation replicated the sucrose cleavage process involved in sugar-smoking through model reactions to obtain distinct model reaction products. The products were analyzed using various techniques such as ultraviolet-visible spectrometry, Fourier-transform infrared spectroscopy, high-performance liquid chromatography, and high-performance liquid chromatography-tandem mass spectrometry. The findings revealed that the pyrolysis of sucrose at 330 °C yielded glucose and fructose, with fructose pyrolysis producing significantly more 5-HMF than glucose. Moreover, the antioxidant capacity of 5-HMF was found to make a substantial contribution. The primary source of 5-HMF was identified as fructose resulting from the cleavage of sucrose at 330 °C, while the primary pathway for the formation of the sugar-smoking pigment 5-GGMF was attributed to the intermolecular dehydration of 5-HMF and glucose at 150 °C.

Preparation and Investigation of Sustained-Release Nanocapsules Containing Cumin Essential Oil for Their Bacteriostatic Properties.

Cumin essential oil chitosan nanocapsules (CENPs) were prepared through the ionic gelation method by blending chitosan (CS) with cumin essential oil (CEO) in different proportions (1:0.8, 1:1, 1:2, 1:3, 1:4). Subsequently, these nanocapsules were characterized and evaluated for their antibacterial properties to determine the optimal cumin essential oil encapsulation and antibacterial efficacy. The outcomes demonstrated that the highest encapsulation efficiency of CENPs was 52%, achieved with a 1:3 CS/CEO ratio. At this point, the nanoparticles had the smallest particle size (584.67 nm) and a regular spherical distribution in the emulsion. Moreover, the CENPs could release the encapsulated CEOs slowly, leading to efficient inhibition of E. coli and L. monocytogenes over a relatively extended period (24-36 h) compared to the CS and CEO. This research offers a promising approach for the use of nanocapsules in food preservation.

Characterization of lamb shashliks with different roasting methods by intelligent sensory technologies and GC-MS to simulate human muti-sensation: Based on multimodal deep learning.

To simulate the functions of olfaction, gustation, vision, and oral touch, intelligent sensory technologies have been developed. Headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC/MS) with electronic noses (E-noses), electronic tongues (E-tongues), computer vision (CVs), and texture analyzers (TAs) was applied for sensory characterization of lamb shashliks (LSs) with various roasting methods. A total of 56 VOCs in lamb shashliks with five roasting methods were identified by HS-SPME/GC-MS, and 21 VOCs were identified as key compounds based on OAV (>1). Cross-channel sensory Transformer (CCST) was also proposed and used to predict 19 sensory attributes and their lamb shashlik scores with different roasting methods. The model achieved satisfactory results in the prediction set (R2 = 0.964). This study shows that a multimodal deep learning model can be used to simulate assessor, and it is feasible to guide and correct sensory evaluation.

Migration of Nutrient Substances and Characteristic Changes of Chicken White Soup Emulsion from Chicken Skeleton during Cooking.

The protein and fat in chicken skeleton can be emulsified in a boiling state to form milky white chicken soup. White chicken soup has a delicious taste, good nutritional value, a beautiful color, and volatile flavor compounds. However, cooking time significantly impacts the quality of white chicken soup. Herein, we investigated the influence of cooking time (30, 60, 90, 120, 150, 180, and 210 min) on the migration of nutrient substances and characteristics changes in white chicken soup from chicken skeletons. The results showed that nutrients such as total lipids, water-soluble protein, total sugars, solid matter, and oligopeptides in the chicken skeletons' tissue continuously migrated into the soup during the cooking process. The total nutrient content in the chicken soup was highest after cooking for 180 min. Simultaneously, the white chicken soup obtained after cooking for 180 min had low interfacial tension and high whiteness, viscosity, and storage stability. The high stability index was associated with increased ζ potential and decreased particle size. The contact angle analysis results also indicated that the stability of the white chicken soup was improved when the cooking time reached 180 min. This research provides basic information for the production of high-quality white chicken soup.

Effects of catechin on the stability of myofibrillar protein-soybean oil emulsion and the adsorbed properties of myosin at the oil-water interface.

The effects of different concentrations of catechin on the stability of myofibrillar protein-soybean oil emulsions and the related mechanisms were investigated. Adding 10 µmol/g catechin had no obvious effects on the emulsion stability and myosin structure, but 50, 100 and 200 µmol/g catechin decreased the emulsion stability. The microstructure observations showed that 10 µmol/g catechin caused a dense and uniform emulsion to form, whereas 50, 100 and 200 µmol/g catechin induced the merging of oil droplets. The addition of 50, 100 and 200 µmol/g catechin caused a decline in both the total sulfhydryl content and surface hydrophobicity, suggesting protein aggregation, which decreased the adsorption capacity of myosin and the elasticity of interfacial film. These results suggested that higher concentrations of catechin were detrimental to the emulsifying properties of myosin and that the dose should be considered when it is used as an antioxidant.

Effect of ultrasound treatment on porcine myofibrillar protein binding furan flavor compounds at different salt concentrations.

The effects of ultrasound (500 W) on the interaction of porcine myofibrillar protein (MP) with furan flavor compounds at different salt concentrations (0.6 %, 1.2 % and 2.4 %) were investigated. With the increase of salt concentration, the particle size of MP decreased, and the surface hydrophobicity and active sulfhydryl content increased due to the unfolding and depolymerization of MP. At the same time, ultrasound promoted the exposure of hydrophobic binding sites and hydrogen bonding sites of MP in different salt concentration systems, thus improving the binding ability of MP with furan compounds by 2 % to 22 %, among which MP had the strongest binding capacity of 2-pentylfuran. In conclusion, ultrasound could effectively promote the unfolding of the secondary structure of MP, which was beneficial to the combination of MP and furan flavor compounds under different salt concentrations.

Effect of fat addition on the characteristics and interfacial behavior of chicken white soup emulsion from chicken skeleton.

The effects of varying fat additions (0 %, 1.0 %, 1.5 %, 2.0 %, and 2.5 %) on characteristics and interfacial properties of chicken white soup emulsion from stewing chicken skeleton were investigated. The results revealed that the chicken white soup emulsion obtained with the 2.0 % fat addition had smaller D3,2 (1.889 µm), D4,3 (2.944 µm), and higher absolute zeta potential value (23.32 mV). Viscosity values were higher for the 2.0 % fat addition compared to the other treatment groups. Techniques like scanning electron microscopy, laser confocal, and atomic force microscopy demonstrated that oil droplets and particles in the soup were smaller and more evenly dispersed with the 2.0 % fat addition. Moreover, the 2.0 % fat group exhibited higher interfacial protein concentration of 207.56 mg/m2. Lastly, low field NMR images confirmed that the stability of the soup was enhanced with a 2.0 % fat addition. This research offers a foundational understanding for producing highly stable chicken white soup.

Using temporal dominance of sensations (TDS), multiple-sip TDS, chemical composition evaluation, and microstructural analysis to assess the impact of repeated reheating cycles on chicken soup.

Reheating chicken soup is a common culinary practice in daily life. To investigate the impact of reheating frequency on the sensory quality of chicken soup, temporal dominance of sensations (TDS) and multi-TDS were used to characterize changes in dominant sensory attributes during consumption. Additionally, E-nose and E-tongue were utilized to analyze differences in aroma and taste profiles. The alterations in sensory properties were further elucidated by analyzing variations in amino acids, volatile compounds. The findings revealed that there was no significant disparity between fresh soup and heating. However, saltiness and umami, as the most prominent dominant characteristics, intensified with increasing reheating cycles. This can be attributed to an elevation in certain amino acids that contribute to umami perception. Conversely, a reduction in some aldehydes weakened the flavor associated with fat and meat components. Moreover, enlarged oil droplets with uneven distribution within heated soup may account for the heightened greasiness sensation.

Design fabrication of electrochemical sensor based on Ru(bpy)22+/SMWCNTs/Au/GCE electrode for the selective determination of 5'-guanosine monophosphate.

5'-Guanosine monophosphate (5'-GMP) is one main source of freshness in broths. Herein, an electrochemical platform based on a novel ternary nanocomposite glassy carbon electrode modified with advantageously-united gold nanoparticles, 2,2'-bipyridine hydrated ruthenium (Ru(bpy)2Cl2) and sulfonated multi-walled carbon nanotubes (SMWCNTs)was prepared and used to detect 5'-GMP. After conditions optimization, the best performance of the electrochemical sensor was found in acidic media, including high specificity, sensitivity and selectivity. The electrochemical sensor exhibited a wide linear range under the optimal conditions. The enhanced sensitivity of this sensor was attributed to the Ru(bpy)2Cl2 and functionalized SMWCNTs that provided high electrical conductivity and electrocatalytic properties during electrochemical reaction. Precise analysis of 5'-GMP in actual broth samples showed satisfactory recovery. Thus, the sensor can be used in the market and food enterprises.

Characterization of selected commercially available grilled lamb shashliks based on flavor profiles using GC-MS, GC × GC-TOF-MS, GC-IMS, E-nose and E-tongue combined with chemometrics.

HS-SPME-GC-MS, SPME-Arrow-GC × GC-TOF-MS, HS-GC-IMS, Electronic-nose, and Electronic-tongue systems were applied in a feasibility study of the flavor characterization of five commercially available Chinese grilled lamb shashliks. A total of 198 volatile organic compounds (VOCs) were identified (∼71% by GC × GC-TOF-MS). Using data fusion strategies, five predictive models were applied to the composition of VOCs and brand identification of the lamb shashliks. Compared with partial least squares regression, support vector machine, deep neural network, and RegBoost modeling, a momentum deep belief network model performed best in predicting VOCs content and identifying shashlik brands (R2 above 0.96, and RMSE below 0.1). Intelligent sensory technology combined with chemometrics is a promising approach to the flavor characterization of shashliks and other food matrices.

Preparation and characterization of diacylglycerol via ultrasound-assisted enzyme-catalyzed transesterification of lard with glycerol monolaurate.

The study aimed to evaluate the effect of ultrasonic pretreatment on the transesterification of lard with glycerol monolaurate (GML) using Lipozyme TL IM to synthesize diacylglycerol (DAG), and the physicochemical properties of lard, GML, ultrasonic-treated diacylglycerol (named U-DAG), purified ultrasonic-treated diacylglycerol obtained by molecular distillation (named P-U-DAG), and without ultrasonic-treated diacylglycerol (named N-U-DAG) were analyzed. The optimized ultrasonic pretreatment conditions were: lard to GML mole ratio 3:1, enzyme dosage 6 %, ultrasonic temperature 80 °C, time 9 min, power 315 W. After ultrasonic pretreatment, the mixtures reacted for 4 h in a water bath at 60 °C, the content of DAG reached 40.59 %. No significant variations were observed between U-DAG and N-U-DAG in fatty acids compositions and iodine value, while P-U-DAG had lower unsaturated fatty acids than U-DAG. Differential scanning calorimetry analysis showed that the melting and crystallization properties of DAGs prepared by ultrasonic pretreatment significantly differed from lard. FTIR spectra noted transesterification reaction from lard and GML with and without ultrasonic pretreatment would not change the structure of lard. However, thermogravimetric analysis proved that N-U-DAG, U-DAG, and P-U-DAG had lower oxidation stability than lard. The higher the content of DAG, the faster the oxidation speed.