Abstract:Food physics studies the physical properties of foods. During the past decades, with the advancement of food science and technology studies, as well as the development of evaluation equipment and devices, studies of food physical properties have made great progress. At the meanwhile, there is a transition in methodological approaches. Currently, the food physical properties studies are shifting from the previous food technology-based studies to the ‘food-human interaction’ and ‘consumer sensory experience’-based scientific investigations. This review mainly introduces the history and evolution of food physical properties studies and the major progress made in recent years, proposing the possible future development directions of food physical property research.

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Abstract:Sugar alcohol has become an ideal sugar substitute sweetener with a promising future because of its pure sweetness, low calories, and advantages of safety and health. However, the research on influencing factors of the sensory properties of sugar alcohol sweeteners was quite limited. In this paper, erythritol, xylitol, maltitol and sorbitol were studied based on the sensory analysis methods such as paired comparison and sorting method. The effects of different particle size, temperatures and solution mass concentrations on the sweetness, coolness, bitterness and off-flavor of sugar alcohols were investigated. The results showed that at room temperature, the coolness of sugar alcohol crystals with different particle sizes showed significant differences (P<0.05), and the sweetness of maltitol and sorbitol also showed significant differences (P<0.01). For both of the two properties, sugar alcohol crystals with larger particle size showed lower intensity. Heat treatment made the off-flavor and bitter taste more easily distinguished among samples with different particles, and weakened the perception of cool and refreshing. Erythritol with high mass concentration showed significant sweetness enhancement in hot drinks. For xylitol, maltitol or sorbitol, the sweetness in cold or hot drinks was similar at different solution mass concentrations.

Abstract:In order to improve the strong fishy smell and insufficient fresh fragrance of oyster peptide Maillard reaction products (MRPs), the effects of exogenous amino acids on the odor and taste characteristics were explored by means of sensory evaluation based on oyster peptide-cysteine-xylose system. The causes of flavor differences were analyzed with the combination of the composition of volatile flavor compounds, the overall odor profile and the relative molecular weight distribution of peptides. The results showed that compared with the addition of glycine or glutamic acid alone, the addition of the two amino acids effectively removed fishy smell and enhanced aroma of oyster peptide MRPs. In addition, the synergistic effect of glycine and glutamic acid significantly reduced the impact of key fishy compounds, such as heptanal and octanal, on the overall odor properties, while the types of volatile flavor components increased to 21, which improved the richness of overall aroma. Meanwhile, the compound addition of exogenous amino acids promoted the degradation of oyster peptides during the Maillard reaction and increased the proportion of flavor peptides with relative molecular weight less than 1 000, which enhanced the taste quality of the system. This study could provide scientific basis for regulating the flavor quality of oyster seasoning.

Abstract:Milk sterilization is essential in milk processing. Different sterilization methods can change the flavour and physico-chemical properties of milk, thus affecting the shelf-life of milk products and consumer preferences. In this study, the physicochemical properties, volatile compounds, and sensory evaluation of raw milk, high-temperature short-time pasteurized milk (HTST milk), and milk treated by infusion technology (INF milk) during storage at 4 ℃ were studied. The study of physico-chemical properties of INF milk showed that its pH decreased significantly, while the particle size and viscosity increased significantly after 30 days storage (P<0.05). In addition, the key flavour compounds in three groups of milk samples were qualitatively and semi-quantitatively analyzed by headspace solid phase extraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) and gas chromatography-olfactory measurement (GC-O). There were 50 volatile compounds detected in milk by HS-SPME-GC-MS, of which 24 could be also detected by GC-O. Among them, some ketones, alcohols, lactones were only measured in INF milk, such as 2-nonanone, 2-butanol, and δ-dodecanol. Moreover, the sweetness and milky flavour of INF milk in sensory evaluation were better than those of HTST milk, however, the aftertaste of INF milk was also heavier. Both HTST milk and INF milk had light cooking flavour. The total concentration of aldehyde in milk was strongly correlated with the sensory evaluation. The results could provide a scientific basis for the rational storage of raw milk, HTST milk, and INF milk.

Abstract:In order to investigate the effect of components on the physical and sensory properties of collagen casing gelatinized candy, the optimal amounts of high and low acyl gellan gum, sucrose and fructose syrup were explored by microstructure, chromaticity analysis, texture analysis and sensory evaluation. The results showed that the amount of low acyl gellan gum was positively correlated with the degree of firmness, hardness and resilience of gelatinous candy, but negatively correlated with smoothness, meltability and wettability. The amount of high acyl gellan gum was positively correlated with the degree of adhesion. Finally, the mass fraction of each substance in collagen casing gelatinous candy with the consumer preference was as follows: deionized water 150%, fructose syrup 80%, sucrose 20%, low acyl gellan gum 1.5%, high acyl gellan gum 1.5%, calcium lactate 1.0% and sodium citrate 0.25%.

Abstract:In order to explore the effects of amylose/amylopectin on the texture characteristics and organoleptic qualities of fish balls from different sources (marine fish/freshwater fish), texture profile analysis (TPA) method was used to determine the texture of fish balls, and the comprehensive assessment of the fish balls texture was then evaluated in combination with organoleptic evaluation. The gel properties of fish balls were studied by water holding capacity analysis and microstructure observation. The results showed that amylopectin could more effectively improve the hardness and chewiness of fish balls compared with amylose. In comparison with the fish balls prepared from basa fish meat, those prepared from mackerel meat had higher content of protein and lower content of fat with superior texture characteristics, organoleptic quality and water retention.

Abstract:With the improvement of people's awareness of sugar reduction, the development of ice cream using sugar substitutes has gained enormous attention. However, sucrose not only provides sweetness, but also plays a critical role in the textural characteristics of ice cream, which is a great challenge for sugar-reduced ice cream. Hereby, the current research is to investigate the effect of various bulking agents on the textural properties of sugar-reduced ice cream, ice cream samples were prepared using sucrose, polyols (sorbitol, erythritol, maltitol, xylitol), soluble dietary fiber (resistant dextrin, polyglucose) and soluble dextrin (maltodextrin) as the bulking agents at a mass fraction of 10%. The sensory texture characteristics and the key physical and chemical properties of ice cream samples were systematically compared. Results showed that the sensory texture profile of ice cream using polydextrose, maltitol or resistant dextrin as the bulking agent was most similar to that of the sample using sucrose as the bulking agent. Comparatively, ice cream using erythritol or maltodextrin as the bulking agent showed high hardness, low plasticity and poor spreadability, while samples using sorbitol or xylitol as the bulking agent had low hardness and high foaminess. The properties of viscosity, particle size distribution and tribological behaviors of samples using polyols as the bulking agents were closer to those of the sample using sucrose as the bulking agent. Particularly, the thermodynamic property of ice creams using maltitol as the bulking agent was quite similar to that of the sample using sucrose as the bulking agent. Besides, samples using dietary fiber or dextrin as the bulking agent exhibited lower friction coefficient and better lubricating property. Accordingly, in the development of sugar-free or sugar-reduced ice cream, a similar texture profile with that of ice cream using sucrose as the bulking agent could be achieved using maltitol combined with polyglucose or resistant dextrin.

Abstract:In order to provide a theoretical basis for the application of annealing treatment in the modification of rice starch, Yuchi early indica rice was used as a raw material and annealed at different temperature (50~70 ℃) and moisture content (45% ~ 65%). Then the starch in the annealed rice was extracted, and the unannealed rice starch was used as the control. The effects of annealing treatment on the solubility, swelling power, gelatinization, digestion and freeze-thaw stability of rice starch were studied. The results showed that compared with the control, the solubility and swelling power of annealed rice starch decreased. The peak viscosity, final viscosity, valley viscosity, retrogradation value and attenuation value decreased, while the gelatinization temperature increased. The effect of annealing temperature on attenuation value was significant. The content of RDS (fast digestible starch) in starch increased, the content of RS (resistant starch) decreased, and the content of SDS (slowly digestible starch) varied with different annealing conditions, indicating that annealing treatment improved the digestibility of rice starch. However, the annealing treatment decreased the freeze-thaw stability of rice starch.

Abstract:Dynamic high-pressure microfluidization (DHPM) were applied to homogenize cellulose polysaccharide (AX), protein (WP), starch (PS) and pectin (PE). The effect of DHPM on the basic properties and structure of macromolecular substances before and after treatment was analyzed by the measurements of particle size, scanning electron microscope, X-ray diffraction (XRD), ultraviolet (UV) absorption spectrum, Fourier transform infrared (FT-IR) spectrum, and apparent viscosity. The results showed that the average particle sizes of four macromolecules after DHPM treatment decreased by 79%, 31%, 68%, and 63%, respectively. The surface of macromolecular particles was sheared and broken to different degrees under the action of shear force. The apparent viscosity of AX and PS increased, while that of WP and PE decreased. The results of XRD, UV absorption and FT-IR spectra showed that there was no change in the characteristic peaks and functional groups before and after homogenization, however, the intensity of the absorption peak varies in different degrees and some absorption peaks were red-shifted. The peak width of stretching vibration characteristic absorption peak of O—H hydrogen bond in AX, PS and PE increased. The α-helix of WP secondary structure disappeared, and the β-sheet content and crystallinity decreased. DHPM treatment could change the properties and structure of the four macromolecules to some extent. This study could provide a theoretical basis for the in-depth development and resource utilization of food macromolecular substances.

Abstract:The objective of this study was to quantitatively investigate the effects of changes in gastrointestinal physiological conditions caused by aging on gastric emptying and dynamic digestion characteristics of cooked rice for the elderly. Based on the differences in the gastrointestinal physiological conditions between the elderly and young adults, the gastric physiological digestive environment of the elderly was constructed by the dynamic in vitro human gastric digestive system. Then, the effects of cold storage time (6, 24, 48 h) at 4 ℃ on the gastric emptying and starch hydrolysis kinetics of the cooked rice during dynamic in vitro gastric digestion for the elderly were investigated. The changes of water content, texture and microstructure of the refrigerated rice were analyzed by static immersion tests. The results showed that with the increase of cold storage duration, a denser microstructure of cooked rice was shown during static soaking, leading to a significantly decreased water holding capacity of rice and the significantly increased indentation hardness of rice. Accordingly, the gastric emptying half-time (t _1/2 ) significantly increased from 303.3 min to 630.6 min, and the starch digestibility decreased from 15.4% to 7.4% after 48 h cold storage. The results showed that the gastric emptying rate of the cooked rice after long-term cold storage would potentially be delayed and the rate of starch hydrolysis might be significantly reduced in the digestive environment of the elderly. This study has provided theoretical guidance for understanding of rice digestion for the elderly and the selection and optimization of food processing/storage methods, contributing to the development of starch-based staple food more suitable for the elderly.

Abstract:In recent years, textured-vegetable-protein-based meat analogs have received more and more attention. The protein digestibility of plant-based meat analogs is still unclear. Sodium bicarbonate is a commonly used additive in the preparation of textured proteins. In order to explore the effect of sodium bicarbonate on the fibrous structure and protein digestibility of textured protein, textured wheat proteins containing 0, 0.05%, and 0.1% (mass fraction of dry powder) sodium bicarbonate were prepared. The fibrous structure was analyzed by measuring the bulk density, texture properties, degree of texturization, microstructure, and protein-protein intermolecular interactions of the samples. The results showed that with the increase of sodium bicarbonate mass fraction from 0 to 0.1%, the bulk density, hardness, and degree of texturization of the textured wheat protein decreased gradually, and the gaps between fibers became larger when the fibers became thinner. After in vitro oral and gastric digestion, the digesta particle size of three textured wheat proteins increased with the increase of sodium bicarbonate concentration (P>0.05). After the simulated small intestinal digestion, the particle sizes of the digestion products of three textured wheat proteins were similar (P>0.05). After 30 min of gastric digestion, the band intensity of protein with relative molecular weight less than 14 300 in three samples declined with the increase of sodium bicarbonate mass fraction. After the in vitro digestion, the content of soluble nitrogen in digesta increased with the increase of sodium bicarbonate mass fraction (P<0.05). These results suggested that the protein digestion rate and degree of textured wheat proteins gradually increased with the increase of sodium bicarbonate mass fraction. After digestion, the total free amino acids obtained released from three textured wheat proteins were （39.53±0.56）, （41.56±0.59）, and （44.85±0.39） mg/g of digesta, respectively. The greater extent of proteolysis in the textured wheat proteins containing the higher mass fractions of sodium bicarbonate might be due to the thinner fibers and more fiber gaps, which promoted the proteases to interact with the cleavage sites.