Effects of Agar Gel Strength and Fat on Oral Breakdown, Volatile Release, and Sensory Perception Using in Vivo and in Vitro Systems

Modulating peppermint oil flavor release properties of emulsion-filled protein gels: Impact of cross-linking method and matrix composition

For some food applications, it is desirable to control the flavor release profiles of volatile flavor compounds. In this study, the effects of crosslinking method and protein composition on the flavor release properties of emulsion-filled protein hydrogels were explored, using peppermint essential oil as a model volatile compound. Emulsion-filled protein gels with different properties were prepared using different crosslinking methods and gelatin concentrations. Flavor release from the emulsion gels was then monitored using an electronic nose, gas chromatography-mass spectrometry (GC-MS), and sensory evaluation. Enzyme-crosslinked gels had greater hardness and storage modulus than heat-crosslinked ones. The hardness and storage modulus of the gels increased with increasing gelatin concentration. For similar gel compositions, flavor release and sensory perception were faster from the heat-crosslinked gels than the enzyme-crosslinked ones. For the same crosslinking method, flavor release and perception decreased with increasing gelatin concentration, which was attributed to retardation of flavor diffusion through the hydrogel matrix. Overall, this study shows that the release of hydrophobic aromatic substances can be modulated by controlling the composition and crosslinking of protein hydrogels, which may be useful for certain food applications.

Using untargeted metabolomics and volatile aroma compounds to predict expert sensory descriptors and consumer liking of beef loin steaks varying in quality grade, aging time, and degree of doneness

Precursors to flavor are important to its development, yet little is known about the intrinsic products of metabolism that influence flavor. Our objective was to use untargeted metabolomics and volatile aroma compounds to predict expert and consumer sensory traits. USDA Select and upper 2/3 Choice beef strip loins were wet aged for 10 or 20 d and then cut into steaks, vacuum-packaged, and frozen. Steaks were cooked to 63 °C, 71 °C, or 80 °C end-point internal steak temperature. USDA Choice steaks had more intense beef flavor identity, brown, roasted, fat-like, salty, sweet, sour, umami, buttery, and overall sweet flavors compared to USDA Select steaks (P < 0.05). Steaks cooked to 80 °C had more intense beef identity, brown, roasted, and umami flavors than steaks cooked to a lower degree of doneness. Steaks cooked to either 63 °C or 71 °C had more intense bloody, metallic, and sour flavors and were juicier, more tender, and had less connective tissue than steaks cooked to a higher degree of doneness. Volatile aroma compounds increased (P < 0.05) in Choice steaks aged for 20 d, while cooking steaks to 80 increased aldehydes, ketones, and pyrazines. Raw steaks had 69 small-molecule metabolomic compounds shared across all four quality grade x aging combinations, and discriminant analysis correctly categorized (P < 0.05) these metabolites. Metabolites and volatiles can be used to predict (r2 > 0.85) expert and consumer sensory panel descriptors and liking.

FTO Regulated Intramuscular Fat by Targeting APMAP Gene via an m6A-YTHDF2-dependent Manner in Rex Rabbits

N6-methyladenosine (m⁶A) regulates fat development in many ways. Low intramuscular fat (IMF) in rabbit meat seriously affects consumption. In order to improve meat quality, we explored the law of IMF deposition. FTO could increase the expression of APMAP and adipocyte differentiation through methylation. However, interference YTHDF2 can partially recover the influence of interference FTO on the APMAP gene and adipocyte differentiation. APMAP promoted the differentiation of adipocytes. Analysis of IMF and APMAP expression showed IMF content is positive with the expression level of the APMAP gene (p < 0.01). Conclusion: Together, FTO can regulate intramuscular fat by targeting the APMAP gene via an m⁶A-YTHDF2-dependent manner in Rex rabbits. The result provides a theoretical basis for the molecular breeding of rabbits.

In vivo and in vitro aroma release in surimi gel with different cross-linking degrees by proton transfer reaction-mass spectrometry

Transglutaminase-induced cross-linking has been suggested as a strategy to govern surimi gels' texture. To achieve the aroma regulation of surimi gels by cross-links, surimi gels were treated with microbial transglutaminase to get different cross-linking degrees, and in vivo and in vitro aroma releases were investigated by a proton transfer reaction-mass spectrometry (PTR-MS). Seventeen compounds in surimi gels were detected by PTR-MS. The in vitro release curves of odorants were fitted by a pseudo-first-order kinetics model. As the cross-links increased, most aroma compounds' released concentrations and release rates decreased first, and then increased significantly (P < 0.05) when the cross-linking degree exceed around 35.4%, negatively related to the springiness and the gel strength of surimi gels. However, the in vivo aroma release results showed that the harder surimi gel released fewer aroma compounds. In conclusion, texture affected by cross-links could be a strategy to control the aroma release of surimi gels.

Effects of fat content on the textural and in vivo buccal breakdown properties of soy yogurt

This study aimed to evaluate the effects of fat content on the textural and in vivo buccal breakdown properties of soy yogurt (SY) at different pH (5.4, 5.0, and 4.6). The microbial analysis, textural and rheological properties, and interfacial protein composition of all the samples were monitored. Microbial results suggested that the increased fat content in SY-5.0 and SY-4.6 resulted in significantly high viable cell counts of lactic acid bacteria (LAB). Textural studies demonstrated that the presence of a low fat content (1-3%) significantly reduced the hardness, springiness, and gumminess of the sample, but this effect was negligible with the addition of fat content (4-5%). The apparent viscosity and thixotropy of the SY-4.6 sample increased as the fat content increased. in vivo buccal digestion showed that a high fat content (2-4%) reduced the number of chews and chewing durations, which might be correlated with high oil droplet release (%) after mastication.

Dynamic Aroma Release from Complex Food Emulsions

In vitro dynamic aroma release over oil-in-water (o/w) and water-in-oil-in-water (w/o/w) emulsions stabilized with Tween 20 or octenyl succinic anhydride (OSA) starch as a hydrophilic emulsifier and polyglycerol polyricinoleate (PGPR) as a hydrophobic emulsifier was investigated. The equal-molecular-weight hydrophilic aroma diacetyl (2,3-butanedione) or relatively more-hydrophobic 3-pentanone was added to the emulsions prepared by high speed mixing, or membrane emulsification followed by thickened with xanthan gum removing droplet size distribution and creaming as variables affecting dynamic release. Results showed the differences of w/o/w emulsions in the dynamic release compared to o/w emulsions mainly depended on aroma hydrophobicity, emulsion type, emulsifier-aroma interactions, and creaming. Xanthan led to a reduced headspace replenishment. Interfacially adsorbed OSA starch and xanthan-OSA starch interaction influenced on diacetyl release over emulsions. OSA starch alone interacted with 3-pentanone. This study demonstrates the potential impact of emulsifying and thickening systems on aroma release systems and highlights that specific interactions may compromise product quality.

Effect of Oral Physiology Parameters on In-Mouth Aroma Compound Release Using Lipoprotein Matrices: An In Vitro Approach

Temporal aroma compound release during eating is a function of the physicochemical properties of the food matrix, aroma compounds, and oral physiology of individuals. However, the influence of each parameter on the release of each aroma component should be clarified. Two flavored lipoprotein matrices varying in composition were chewed in a chewing simulator that reproduced most of the physiological functions of the mouth. Aroma compound releases (butanoic acid, 2-heptanone, ethyl butyrate, 3-octanone, and 2-nonanone) were followed in real time by direct connection of the device to APCI-MS (atmospheric pressure chemical ionization mass spectrometry). Each oral parameter was controlled and decoupled using the in vitro device. The food matrix composition had only a low impact on aroma compound release, but the controlled oral parameters had significantly different influences on the release of aroma compounds according to their physicochemical characteristics. The release of certain compounds seemed more sensitive to bite force, while others seemed more sensitive to the shearing angle. The salivary flow rate primarily influenced the more hydrophobic compounds. Significant interactions were also observed between shear angle, salivary flow rate, and lipoprotein matrix composition, mainly for the release of the more hydrophobic volatile compounds; this needs further investigations to be clarified.

Integration of Bacterial Expansin on Agarolytic Complexes to Enhance the Degrading Activity of Red Algae by Control of Gelling Properties

Expansin act by loosening hydrogen bonds in densely packed polysaccharides. This work characterizes the biological functions of expansin in the gelling and degradation of algal polysaccharides. In this study, the bacterial expansin BpEX from Bacillus pumilus was fused with the dockerin module of a cellulosome system for assembly with agarolytic complexes. The assembly of chimeric expansin caused an indicative enhancement in agarase activity. The enzymatic activities on agar substrate and natural biomass were 3.7-fold and 3.3-fold higher respectively than that of agarase as a single enzyme. To validate the effect on the agar degradation, the regulation potential of parameters related to gel rheology by bacterial expansin was experimentally investigated to indicate that the bacterial expansin lowered the gelling temperature and viscosity of agar. Thus, these results demonstrated the possibility of advancing more efficient strategies for utilizing agar as oligo sugar source in the biorefinery field that uses marine biomass as feedstocks.

Effect of marbling on volatile generation, oral breakdown and in mouth flavor release of grilled beef

While the positive effect of intramuscular fat (IMF) on beef tenderness is well-established, its role in flavor generation and flavor release is less defined. To increase understanding, real-time volatile generation was monitored during grilling of beefsteaks (grass and grain-fed Angus and grass-fed Wagyu) with different amounts of IMF by proton transfer reaction mass spectrometry. Volatile concentration increased significantly (p<0.001) when the IMF was >~10%, but did not differ (p>0.05) at lower IMF levels (5.2-10.2%). In vivo release of volatiles during consumption of grilled steaks was also measured using human subjects. Pre- and postswallow volatile release profiles varied according to marbling level and volatile fat solubility. In-mouth release of key hydrophilic volatiles was significantly greater (p<0.05) in high IMF grilled beef, consistent with more intense sensory flavor. Faster oral breakdown and higher peak saliva concentrations of non-volatile flavor compounds in high IMF grilled beef were consistent with higher tenderness and more intense flavor perception.

Characteristics of Hanwoo cattle and health implications of consuming highly marbled Hanwoo beef

This review addresses the unique characteristics of Hanwoo cattle and potential health implications of consuming highly marbled Hanwoo beef. The Hanwoo breed has high genetic potential for accumulating intramuscular fat (IMF) and producing highly marbled beef. The high level of marbling is achieved through increasing levels of concentrated feed with an extended finishing period. In response to consumer preferences, the level of marbling of Hanwoo beef has been increasing. The IMF content can be manipulated depending on the feeding duration, finishing diet, and genotype. On the other hand, some consumers are expressing concern regarding the consumption of too much animal fat. This review discusses the potential of Hanwoo beef as a dietary source of heart-healthy fats. Highly marbled Hanwoo beef has a high proportion of monounsaturated fatty acid (MUFA) due to the presence of abundant oleic acid. Literature indicates that MUFAs are heart-healthy dietary fats because they can lower low-density lipoprotein (LDL)-cholesterol while increasing high-density lipoprotein (HDL)-cholesterol. Also, recent clinical trials have indicated that highly marbled beef does not increase LDL-cholesterol and consistently increases HDL-cholesterol. Finally, the current work emphasizes that consumption of high oleic acid Hanwoo beef might potentially reduce risk factors for cardiovascular disease, and may become accepted as a healthy well-being food.

Composite foods: from structure to sensory perception

This review article gives an overview of structural features of composite foods, and its relation to rheological, lubrication and sensory properties.

Consumer Acceptability of Intramuscular Fat

Fat in meat greatly improves eating quality, yet many consumers avoid visible fat, mainly because of health concerns. Generations of consumers, especially in the English-speaking world, have been convinced by health authorities that animal fat, particularly saturated or solid fat, should be reduced or avoided to maintain a healthy diet. Decades of negative messages regarding animal fats has resulted in general avoidance of fatty cuts of meat. Paradoxically, low fat or lean meat tends to have poor eating quality and flavor and low consumer acceptability. The failure of low-fat high-carbohydrate diets to curb "globesity" has prompted many experts to re-evaluate of the place of fat in human diets, including animal fat. Attitudes towards fat vary dramatically between and within cultures. Previous generations of humans sought out fatty cuts of meat for their superior sensory properties. Many consumers in East and Southeast Asia have traditionally valued more fatty meat cuts. As nutritional messages around dietary fat change, there is evidence that attitudes towards animal fat are changing and many consumers are rediscovering and embracing fattier cuts of meat, including marbled beef. The present work provides a short overview of the unique sensory characteristics of marbled beef and changing consumer preferences for fat in meat in general.