Determination of Aroma Compound Partition Coefficients in Aqueous, Polysaccharide, and Dairy Matrices Using the Phase Ratio Variation Method: A Review and Modeling Approach

Addressing flavor challenges in reduced-fat dairy products: A review from the perspective of flavor compounds and their improvement strategies

In recent years, the demand for reduced-fat dairy products (RFDPs) has increased rapidly as the health risks associated with high-fat diets have become increasingly apparent. Unfortunately, lowering the fat content in dairy products would reduce the flavor perception of fat. Fat-derived flavor compounds are the main contributor to appealing flavor among dairy products. However, the contribution of fat-derived flavor compounds remains underappreciated among the flavor improvement factors of RFDPs. Therefore, this review aims to summarize the flavor perception mechanism of fat and the profile of fat-derived flavor compounds in dairy products. Furthermore, the characteristics and influencing factors of flavor compound release are discussed. Based on the role of these flavor compounds, this review analyzed the current and potential flavor improvement strategies for RFDPs, including physical processing, lipolysis, microbial applications, and fat replacement. Overall, promoting the synthesis of milk fat characteristic flavor compounds in RFDPs and aligning the release properties of flavor compounds from the RFDPs with those of equivalent full-fat dairy products are two core strategies to improve the flavor of reduced-fat dairy products. In the future, better modulation of the behavior of flavor compounds by various methods is promising to replicate the flavor properties of fat in RFDPs and meet consumer sensory demands.

Effects of gallic acid on the release of aroma compounds in Moutai Baijiu

Due to the trace concentrations of gallic acid (GA), the interaction mechanism between GA and flavor compounds is limited, and the effects on the aroma compounds of Moutai Baijiu are even more unclear. In this study, the aroma compounds and phenolic compounds in Moutai Baijiu were investigated by stir bar sorptive extraction (SBSE), gas chromatography-olfactometry (GC-O), gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS). A total of 63 volatiles and 10 phenolic compounds were identified, and 16 esters and 4 alcohols were identified as the important aroma substances (odor activity values ≥1). The effect of GA on the release of aroma compounds was investigated by sensory analysis and partition coefficient. The results showed that GA mainly inhibited the volatilization of alcohols, low concentrations of GA promoted the release of esters, and high concentrations slowed down or even inhibited the release effect affected by the hydrophobicity of aroma compounds. UV spectroscopy and thermodynamic analysis further revealed that the interaction of GA with 1-propanol was attributed mainly to hydrogen bonding and van der Waals forces, and the interaction with other compounds was mainly influenced by hydrophobic effects. These results show that gallic acid can effectively control the release of the aromas of Moutai Baijiu, highlight the important role of GA on the volatiles of baijiu, and provide theoretical support for further healthy improvement of the sensory quality of baijiu.

Flavor-food ingredient interactions in fortified or reformulated novel food: Binding behaviors, manipulation strategies, sensory impacts, and future trends in delicious and healthy food design

With consumers gaining prominent awareness of health and well-being, a diverse range of fortified or reformulated novel food is developed to achieve personalized or tailored nutrition using protein, carbohydrates, or fat as building blocks. Flavor property is a critical factor in the acceptability and marketability of fortified or reformulated food. Major food ingredients are able to interact with flavor compounds, leading to a significant change in flavor release from the food matrix and, ultimately, altering flavor perception. Although many efforts have been made to elucidate how food matrix components change flavor binding capacities, the influences on flavor perception and their implications for the innovation of fortified or reformulated novel food have not been systematically summarized up to now. Thus, this review provides detailed knowledge about the binding behaviors of flavors to major food ingredients, as well as their influences on flavor retention, release, and perception. Practical approaches for manipulating these interactions and the resulting flavor quality are also reviewed, from the scope of their intrinsic and extrinsic influencing factors with technologies available, which is helpful for future food innovation. Evaluation of food-ingredient interactions using real food matrices while considering multisensory flavor perception is also prospected, to well motivate food industries to investigate new strategies for tasteful and healthy food design in response to consumers' unwillingness to compromise on flavor for health.

Recent trends in aroma release and perception during food oral processing: A review

The dynamic and complex peculiarities of the oral environment present several challenges for controlling the aroma release during food consumption. They also pose higher requirements for designing food with better sensory quality. This requires a comprehensive understanding of the basic rules of aroma transmission and aroma perception during food oral processing and its behind mechanism. This review summarized the latest developments in aroma release from food to retronasal cavity, aroma release and delivery influencing factors, aroma perception mechanisms. The individual variance is the most important factor affecting aroma release and perception. Therefore, the intelligent chewing simulator is the key to establish a standard analytical method. The key odorants perceived from the retronasal cavity should be given more attention during food oral processing. Identification of the olfactory receptor activated by specific odorants and its binding mechanisms are still the bottleneck. Electrophysiology and image technology are the new noninvasive technologies in elucidating the brain signals among multisensory, which can fill the gap between aroma perception and other senses. Moreover, it is necessary to develop a new approach to integrate the relationship among aroma binding parameters, aroma concentration, aroma attributes and cross-modal reactions to make the aroma prediction model more accurate.

Effects of Organic Acids on the Release of Fruity Esters in Water: An Insight at the Molecular Level

It is well known that organic acids (OAs) could affect the flavour of fruit juices and beverages. However, the molecular mechanism of aroma release is still unclear. In this study, the effects of citric acid (CA), L-(-)-malic acid (MA) and L-lactic acid (LA) on the release of six selected esters and their sensory perception were investigated by means of HS-GC-MS analyses and odour detection threshold determination, respectively. Meanwhile, the density functional theory (DFT) calculation was employed to explore the interaction modes between esters and OAs. HS-GC-MS analyses showed that the concentration and the type of OAs regulated the release of esters. The results were basically consistent with the detection threshold change of those esters. The DFT calculation suggested that the main intermolecular interaction was hydrogen bonds, and several esters could form a ternary ring structure with OAs through hydrogen bonds. The interactions can induce the different release behaviours of esters in OAs water solution. The number of carboxyl functional groups in OAs and the spatial conformation of esters appeared to influence the magnitude of the interaction. The above results demonstrated the mechanism of OAs affecting the release of esters and indicated a possible flavour control way by using different OAs and OA concentrations.

Studying dynamic aroma release by headspace-solid phase microextraction-gas chromatography-ion mobility spectrometry (HS-SPME-GC-IMS): method optimization, validation, and application

To understand aroma perception from complex food matrices' determination of dynamic aroma release during simulated oral processing is necessary. In this study optimization, validation and application of a novel method coupling headspace-solid phase microextraction (HS-SPME) with gas chromatography-ion mobility spectrometry (GC-IMS) is presented. Thirteen character impact compounds imparting different chemical properties are studied to understand capabilities and limitations of the method. It was shown for the first time that the temperature of the IMS sample inlet can be increased up to 200 °C without instrumental constraints. Linear calibration was possible for eleven of the thirteen compounds with one decade dynamic range. The limit of detection and quantitation were 2.1-63.0 ppb and 7.2-210.1 ppb, respectively. Diacetyl could be detected in negative polarity mode of IMS, however with lower precision compared to the compounds detected in positive mode. Limitations of the method were short HS-SPME extraction time, which in the case of caproic acid was not sufficient for reliable quantification. Additionally, δ-decalactone could not be detected due to maximum GC temperature of 200 °C. Application of the method to determine dynamic aroma release from a dairy matrix was successfully shown for nine compounds. Analysis of complex food matrix was performed with similar precision compared to analysis in aqueous solution, thus proving high robustness of the method towards matrix effects.