Michelle J.Y. Yoo

The Role of Oral Processing in Dynamic Sensory Perception

Food oral processing is not only important for the ingestion and digestion of food, but also plays an important role in the perception of texture and flavor. This overall sensory perception is dynamic and occurs during all stages of oral processing. However, the relationships between oral operations and sensory perception are not yet fully understood. This article reviews recent progress and research findings on oral food processing, with a focus on the dynamic character of sensory perception of solid foods. The reviewed studies are discussed in terms of both physiology and food properties, and cover first bite, mastication, and swallowing. Little is known about the dynamics of texture and flavor perception during mastication and the importance on overall perception. Novel approaches use time intensity and temporal dominance techniques, and these will be valuable tools for future research on the dynamics of texture and flavor perception.

The effect of background music on food pleasantness ratings

This study investigated whether samples of pleasant, neutral and unpleasant music can impact food perception. To this end, the pleasantness of three different types of chocolate gelati (milk chocolate, dark chocolate and bittersweet chocolate) was determined using 50 participants exposed to silence (the reference condition) and three music samples differing in self-rated preference. To measure hedonic responses to the gelati samples, the Time Intensity method was utilized to derive the maximum intensity of pleasantness and the area under the Time Intensity pleasantness curve. The presence of non-preferred music significantly decreased the pleasantness ratings of all three types of chocolate gelati tested, while preferred music increased perceived pleasantness ratings of dark and bittersweet chocolate gelati, but not milk chocolate gelato. Time Intensity parameters for pleasantness ratings did not differ significantly across the three different types of chocolate gelati in the silent condition, suggesting that listening to the music influenced gelati pleasantness ratings. This study demonstrated that the pleasantness of gelati changed with music valence. The findings echo previous studies emphasizing the importance of crossmodal effects between music and food perception.

Hydrolysis by Alcalase Improves Hypoallergenic Properties of Goat Milk Protein

Goat milk is highly nutritious and is consumed in many countries, but the development of functional foods from goat milk has been slow compared to that for other types of milk. The aim of this study was to develop a goat milk protein hydrolysate (GMPH) with enhanced digestibility and better hypoallergenic properties in comparison with other protein sources such as ovalbumin and soy protein. Goat milk protein was digested with four commercial food-grade proteases (separately) under various conditions to achieve the best hydrolysis of αs -casein and β-lactoglobulin. It was shown that treatment with alcalase (0.4%, 60℃ for 30 min) effectively degraded these two proteins, as determined by SDS-PAGE, measurement of nonprotein nitrogen content, and reverse-phase high-performance liquid chromatography. Hydrolysis with alcalase resulted in a significant decrease in β-lactoglobulin concentration (almost to nil) and a ~40% reduction in the level of αs-casein. Quantification of histamine and TNF-α released from HMC-1 cells (human mast cell line) showed that the GMPH did not induce an allergic response when compared to the control. Hence, the GMPH may be useful for development of novel foods for infants, the elderly, and convalescent patients, to replace cow milk.

Effect of (−)-epigallocatechin gallate (EGCG) extracted from green tea in reducing the formation of acrylamide during the bread baking process

This is the first study to investigate the extent of reduction in acrylamide formation during baking with the addition of (-)-epigallocatechin gallate (EGCG) extracted from green tea, and to determine whether EGCG influences the texture and colour attributes of bread, or interacts with other ingredients. EGCG powders were added to white bread formulations at the concentrations of 3.3, 6.6 and 9.9g·kg-1. The amount of acrylamide in the bread was analysed using liquid chromatography-mass spectrometry. EGCG addition significantly reduced the acrylamide formation by 37% compared to the control and decreased the moisture content of the bread by 6%. It did not affect its texture attribute, but increased the lightness and the yellowness and decreased the redness of bread crust (with contrasting results in crumb). It also decreased granule size and porosity. In conclusion, EGCG fortification is a feasible method to decrease acrylamide formation in baked bread.

Novel meat-enriched foods for older consumers

Red meat enriched versions of bread, spaghetti, yoghurt, ice cream and chocolate were prototyped and assessed for some of their physical, chemical and microbiological properties, as well as sensory appeal. The protein content of the products were significantly increased and their colour went darker with meat enrichment (p<0.05). Bread volume and spaghetti tensile strength increased and ice cream meltability and yoghurt apparent viscosity decreased with meat enrichment (p<0.05). The overall acceptability/liking of bread, flavoured ice cream and spaghetti were not affected (p>0.05) but that of non-flavoured ice cream and yoghurt went down (p<0.05) with meat enrichment. 75% of the 940 panellist who ate the meat-enriched chocolates either loved or slightly-liked them. The outcome of the present study would assist in making the nutrition of meat available in a wider range of product categories, helping the meat industry stretch its established business models, and encouraging further development of novel food choices for elderly and other groups of consumers.

Effect of animal age on the nutritional and physicochemical qualities of ovine bresaola

Bresaola made from New Zealand mutton and lamb, were compared in quality attributes. Mutton bresaola had slightly lower protein and higher moisture contents, and similar amount of intramuscular fat and instrumental colour compared to that of the lamb. 36 and 80 unique endogenous peptides were observed in mutton and lamb, respectively. Proteolysis during dry-curing was affected by the age of the animal and has resulted in softer and easier to chew textural properties to the mutton bresaola. Significantly higher amounts of total free amino acids and higher proportion of essential amino acids were detected in the mutton bresaola from digestion simulation compared to that from lamb. Expedited proteolysis measured in the form of the release of free amino acids was positively related to the animal age. Overall, bresaola from mutton had more favourable characteristics compared to that of the lamb.

Evaluation of the Digestibility of Korean Hanwoo Beef Cuts Using the in vitro Physicochemical Upper Gastrointestinal System

The aim of this study was to investigate the digestibility of different Korean Hanwoo beef cuts using an in vitro digestion model, in vitro physicochemical upper gastrointestinal system (IPUGS). The four most commonly consumed cuts — tenderloin, sirloin, brisket and flank, and bottom round — were chosen for this study. Beef samples (75 g) were cooked and ingested into IPUGS, which was composed of mouth, esophagus, and stomach, thereby simulating the digestion conditions of humans. Digested samples were collected every 15 min for 4 h of simulation and their pH monitored. Samples were visualized under a scanning electron microscope (SEM) to examine changes in the smoothness of the surface after digestion. Analysis of the amino acid composition and molecular weight (MW) of peptides was performed using reverse-phase high performance liquid chromatography and sodium dodecyl sulfate polyacrylamide gel electrophoresis, respectively. Following proteolysis by the gastric pepsin, beef proteins were digested into peptides. The amount of peptides with higher MW decreased over the course of digestion. SEM results revealed that the surface of the digested samples became visibly smoother. Total indispensable and dispensable amino acids were the highest for the bottom round cut prior to digestion simulation. However, the total amount of indispensable amino acids were maximum for the tenderloin cut after digestion. These results may provide guidelines for the elderly population to choose easily digestible meat cuts and products to improve their nutritional and health status.