Amino Acid Taste Research Articles

Enhancing the quality of semi-dried tilapia fillets using ultraviolet radiation to simulate the natural solar drying process: Integration of flavoromics, lipidomics, and targeted metabolomics

Ultraviolet light from the sun plays an important role in the formation of the quality of natural air-dried meat products. This study investigated the effect of UV-simulated sunlight-assisted drying on the quality of tilapia fillets by lipidomics, targeted metabolomics, and flavoromics. The results showed that UV radiation increased the gap between myofibrils. UV radiation moderately improved lipid oxidation levels and changed the flavor profile. The volatiles of the UVA or UVB groups were more abundantly and diverse than those of the other groups. The contents of taste amino acids and nucleotides were increased after UV radiation. 422 lipid molecules were identified, of which 66 differential lipids were screened. UV radiation promoted the volatiles production by accelerating the degradation of differential lipids. Best organoleptic quality of products were obtained after UVA or UVB radiation. This study provides new horizons for improving the flavor of dried meat products.

Decoding the Molecular Mechanism of Sweet Taste of Amino Acids by Their Intrinsic Properties and Interactions with Human Sweet Taste Receptor

AbstractThe molecular basis of sweet taste toward various amino acids has not been fully elucidated. In this study, by correlation of their sweetness intensities with molecular properties, it is revealed that hydrophobic or dispersion force between side chains and sweet taste receptor (Tas1R2/Tas1R3) plays a prominent role for eliciting sweetness. Furthermore, the interaction modes of 13 amino acids with receptor indicate that amino (AH) and carboxyl (B) glucophores of different amino acids interact with identical residues of receptor, while the hydrophobic side chains (X glucophores) conduct distinct topological orientations with receptor, determining their chirality selection and sweetness intensities. Molecular dynamics analysis shows that sweet d‐amino acids move toward the hydrophobic transmembrane domain during activation with more contact numbers with receptor than nonsweet l‐amino acids, providing a mechanistic elucidation of previous inconsistent sensory evaluation results of specific amino acids. Moreover, by comparison with the interactions of a dipeptide sweetener, aspartame with Tas1R2/Tas1R3 and nonsweet l‐glutamate with class C G protein‐coupled receptors, we conclude that a complementary interaction mode with both hydrophilic and hydrophobic contacts accounts for the molecular origin of their sweet taste, presenting in‐depth insights and valuable guidelines for further molecular designs or modifications of amino acids‐derived sweeteners.

Functionality, physicochemical properties, and applications of chitosan/nano-hydroxyapatite–tea polyphenol films

An active chitosan (CS) film containing a nano-hydroxyapatite–tea polyphenol (HAP-TP) complex was designed and prepared. The effects of HAP-TP loading on the structural and physicochemical properties of the CS-based film were evaluated. The mechanical and thermal properties of the film were significantly improved by the resulting intermolecular interactions and formation of hydrogen bonds between HAP-TP and CS, which reduced the water vapor and oxygen permeabilities of the film by 29.78 and 35.59 %, respectively. The CS-HAP-TP film exhibited excellent slow-release behavior and antioxidant activity, with a cumulative release rate at 700 h 6.79 % lower than that of CS-TP films. The CS-HAP-TP film significantly inhibited the deterioration of semi-dried golden pompano, and thus helped to retain the taste of umami and sweet amino acids in fish samples, while reducing off-flavor generation. The film therefore shows considerable potential as an active packaging material for the preservation of semi-dried fish products.

Comparison of Different Deodorizing Treatments on the Flavor of Paddy Field Carp, Analyzed by the E-Nose, E-Tongue and Gas Chromatography-Ion Mobility Spectrometry.

Changes in the flavor and taste profiles of Paddy Field Carp after deodorization with perilla juice (PJ), cooking wine (CW) and a mixture of the two (PJ-CW) were analyzed using the E-nose, E-tongue, gas chromatography-ion mobility spectrometry (GC-IMS), free amino acid analysis and taste nucleotide analysis. The E-nose and E-tongue revealed that deodorization reduced the content of sulfur-containing compounds, enhanced umami, bitterness, sourness and astringency, and decreased saltiness. PCA and OPLS-DA analysis successfully distinguished between the effects of the treatments. Free amino acids increased from 8777.67 to 11,125.98 mg/100 g and umami amino acids increased from 128.24 to 150.37 mg/100 g after PJ-CW deodorization (p < 0.05). Equivalent umami concentration (EUC) comparisons showed that PJ-CW treatment produced the greatest synergistic umami enhancement (to 3.15 g MSG equiv./100 g). GC-IMS detected 52 aroma compounds; PJ treatment produced the greatest diversity of aldehydes, including heptanal, nonanal, hexanal, 3-methylbutanal, (E)-2-heptenal and (E,E)-2,4-heptadienal. The total content of volatile flavor compounds was the highest after PJ-CW treatment, and the content of many characteristic flavor substances (3-hydroxy-2-butanone, benzaldehyde, 5-methyl-2(3H)-furanone) increased. These findings provided a theoretical basis for the further development of deodorization methods for Paddy Field Carp.

Comparative analysis of nutritional and non-volatile taste components of the Chinese mitten crab (Eriocheir sinensis)

This study investigated the differences among 20–20 individual crab samples from Chongming (CM) and Taixing (TX) origin in china through proximate composition, taste composition, and sensory analysis evaluation, to find out the key factors and contribute to the realization of the high-quality mitten crab culture industry. The results showed that the overall performance of TX group was better, and the contents of Ala, Gly, Arg and AMP were 6.33±1.25 mg/g, 4.67±0.87 mg/g, 4.53±0.69 mg/g and 68.68±22.88 mg/100 g, respectively. The key taste amino acids, whose taste activity value was over 1.0, detected in TX (5 kinds) and CM (4 kinds). The umami and sweet sensory scores of TX were 0.52 and 0.50 higher than that in CM group. Cluster analysis and principal component analysis showed that TX and CM crabs could be distinguished to a certain extent.

Flavour characterization of twelve species of edible algae

Integration of algae as ingredients in food products may contribute to the flavour characteristics, on top of providing nutritional requirements. In this study, characterization of the volatile and non-volatile flavour compounds was performed on 12 species of macroalgae and microalgae representing various groups of algae. Nine macroalgae species from three divisions were selected, namely Phaeophyta (brown alga): Laminaria japonica, Undaria pinnatifida, Sargassum fusiforme and Fucus vesiculosus; Rhodophyta (red alga): Porphyra haitanensis, Porphyra yezoensis, Palmaria palmata and Gelidium amansii, and Chlorophyta (green alga): Ulva lactuca. In addition, three microalgae species include Arthrospira platensis, Chlorella vulgaris and Dunaliella salina. Volatile compounds were analysed by solid-phase microextraction (SPME) and gas chromatography–mass spectrometry-flame ionization detector (GC–MS/FID). Amino acids and nucleotides were analysed using amino acid analyser and high-performance liquid chromatography (HPLC) respectively. Based on the identified volatile and non-volatile compounds, no obvious trend was found within each group of algae. However, some algae variants have been found to contain a unique aroma profile of selected volatile and non-volatile compounds. D. salina was found to be high in volatile aldehydes, ketones, and alcohols, primarily products of carotenoid degradation. U. lactuca contains the highest volatile sulfur content, while F. vesiculosus was found to be high in aldehyde and alcohol compounds, which are potentially fishy odours. C. vulgaris was found to have the highest value of equivalent umami concentration (EUC) followed by roasted P. haitanensis, indicating that both algae have the highest umami potential. Lastly, microalgae species A. platensis and C. vulgaris contained the highest amounts of sulfurous tasting amino acids cysteine and methionine respectively.

Characterization of Amino Acid Composition, Nutritional Value, and Taste of Fruits from Different Actinidia arguta Resources

The nutritional value and flavor and texture characteristics of fruits from different Actinidia argute resources were scientifically evaluated and compared. Using 35 A. arguta fruits as materials, the amino acid composition and content were determined by an automatic amino acid analyzer, and differentiation analysis, amino acid nutritional value evaluation, TAV flavor analysis, correlation analysis, PCA comprehensive evaluation, and cluster analysis were conducted to clarify the diversity of A. arguta resources in terms of amino acid content, composition, and flavor characteristics. Analysis of differential results showed that the A. arguta resource fruits contained 17 amino acids with a total amino acid content of 384.20∼2590.56 mg/100 g. The results of the nutritional value evaluation showed that the Leu of the fruits of the A. arguta resources all conformed to the ideal model proposed by FAO/WHO, and the Leu content of all the resources exceeded the human body’s needs, and it was also found that the first limiting amino acid of the Actinidia argute resources was Ile and the second limiting amino acid was Lys. TAV of the flavor-presenting amino acids was calculated to evaluate the flavor-presenting taste characteristics, and the amino acids that influenced the flavor of A. arguta fruit were Glu and Cys. PCA showed that the 2 principal components could better reflect the comprehensive information of amino acids in A. arguta, and the cumulative variance contribution rate was 87.88%, which could represent the main trend of amino acids in A. arguta. A comprehensive amino acid evaluation model was established, and the composite scores indicated that the top 5 excellent resources were S4, S10, S18, S25, and S30. Hierarchical cluster analysis classified the 35 A. arguta resources into 4 categories, which better reflected the differences in amino acid content and composition, nutritional value, and taste characteristics among A. arguta fruits from different collection sites.

Impact of feeding diets with enhanced vegetable protein content and presence of umami taste-stimulating additive on gastrointestinal amino acid sensing and feed intake regulation in rainbow trout

The regulation of feed intake in fish is dependent upon different neuroendocrine and metabolic mechanisms including amino acid sensing in the gastrointestinal tract (GIT). However, there is little information regarding the impact of diets on such mechanisms. Therefore, in this study, we fed rainbow trout (Oncorhynchus mykiss) with 3 diets: a diet with high content of fishmeal and low content of soybean protein concentrate (SPC) (HF), a diet with a reduced content of fishmeal and high content of SPC (LF), and the LF diet supplemented with an umami taste-stimulating additive (LFU). Fish were fed ad libitum once a day for 4 weeks, with no significant differences being registered in feed intake among groups. At the end of the feeding trial, we collected samples of different areas of the GIT (stomach, proximal and distal intestine) and hypothalamus at different times: after 48 h of fasting (time 0), and 1 h, 4 h, and 24 h after feeding. We evaluated the activity of pepsin in the stomach and trypsin and chymotrypsin in the proximal intestine, as well as mRNA abundance of transcripts encoding amino acid transporters and taste receptors, intracellular signalling molecules, and hormones. Moreover, we assessed the hypothalamic mRNA abundance of neuropeptides involved in feed intake regulation. Feeding rainbow trout with LF did not result in marked alterations in parameters related to digestive function and amino acid sensing in the rainbow trout GIT, nor in the expression of gastrointestinal hormones (except cck) and hypothalamic neuropeptides. In contrast, supplementation of the LF diet with an umami taste-stimulating additive resulted in a general improvement of digestive or absorptive function (increased protein, dry matter and energy digestibility, and earlier peak in plasma amino acid levels) and activation of gut-brain axis mechanisms involved in feed intake regulation through the transcriptional activation of amino acid transporters, taste receptors, signalling molecules, and hormones. These results demonstrate that the dietary inclusion of umami receptor stimulants has the potential to improve fish physiological responses to the rise in levels of vegetable protein in the diet.

The avian taste system.

Taste or gustation is the sense evolving from the chemo-sensory system present in the oral cavity of avian species, which evolved to evaluate the nutritional value of foods by detecting relevant compounds including amino acids and peptides, carbohydrates, lipids, calcium, salts, and toxic or anti-nutritional compounds. In birds compared to mammals, due to the relatively low retention time of food in the oral cavity, the lack of taste papillae in the tongue, and an extremely limited secretion of saliva, the relevance of the avian taste system has been historically undermined. However, in recent years, novel data has emerged, facilitated partially by the advent of the genomic era, evidencing that the taste system is as crucial to avian species as is to mammals. Despite many similarities, there are also fundamental differences between avian and mammalian taste systems in terms of anatomy, distribution of taste buds, and the nature and molecular structure of taste receptors. Generally, birds have smaller oral cavities and a lower number of taste buds compared to mammals, and their distribution in the oral cavity appears to follow the swallowing pattern of foods. In addition, differences between bird species in the size, structure and distribution of taste buds seem to be associated with diet type and other ecological adaptations. Birds also seem to have a smaller repertoire of bitter taste receptors (T2Rs) and lack some taste receptors such as the T1R2 involved in sweet taste perception. This has opened new areas of research focusing on taste perception mechanisms independent of GPCR taste receptors and the discovery of evolutionary shifts in the molecular function of taste receptors adapting to ecological niches in birds. For example, recent discoveries have shown that the amino acid taste receptor dimer T1R1-T1R3 have mutated to sense simple sugars in almost half of the living bird species, or SGLT1 has been proposed as a part of a T1R2-independent sweet taste sensing in chicken. The aim of this review is to present the scientific data known to date related to the avian taste system across species and its impact on dietary choices including domestic and wild species.

Impact of drying methods on physicochemical properties of Fritillaria hupehensis (Hubeibeimu) flours

Fritillaria hupehensis (Hubeibeimu) widely grows in the mid-western zones of China. In the present work, we investigated the physicochemical compositions, antioxidant abilities, and thermal properties of the bulbs of F. hupehensis dehydrated by heat-pump drying (HD), vacuum drying (VD), natural drying (ND), freeze drying (FD), and microwave drying (MD). Total contents of nucleosides and nucleobases in F. hupehensis flours ranged from 727.64 to 1,654.25 μg/g, and total free amino acids ranged from 88.03 to 128.21 mg/g. FD flour had high contents of total nucleosides and nucleobases, and free amino acids. MD flour had low contents of total starch, amylose, protein, nucleosides and nucleobases, and VB1 and VB2, and high levels of total phenolic content (TPC) and antioxidant abilities. Furthermore, MD flour facilitated gelatinisation, while FD flour displayed opposite trend. HD flour had high total starch content, while ND flour weakened the bitter taste due to the percentage of sweet and bitter taste of amino acids.

Composition of Flavour Non Volatile Compound Steamed Gourami (Osphronemus gouramy)

This research aims to identify the composition of non-volatile flavor compounds contained in the steamed gourami (Osphronemus gouramy). The research was carried out experimentally with the treatment of steamed gourami samples (at 100℃ for ± 30 minutes). This research was conducted at the Fisheries Product Processing Laboratory, Faculty of Fisheries and Marine Sciences, Padjadjaran University, Jatinangor; IPB Integrated Laboratory. A simple product description test was carried out on samples which included the appearance of the meat, aroma, texture, and taste. Identification of non-volatile flavor compounds using tools High Performance Liquid Chromatography (HPLC). The results showed that steamed gourami has 15 identified non-volatile flavor compounds of 15 amino acid compounds. Two umami-flavored amino acids are 4.09% glutamic acid and 2.67% aspartic acid. The four sweet tasting amino acids are 1.53% alanine, 1.19% threonine, 1.13% glycine and 1.01% serine. The nine bitter amino acids are lysine 2.54%, leucine 2.11%, arginine 1.64%, valine 1.30%, isoleucine 1.29%, phenylalanine 1.14%, tyrosine 0.91%, methionine 0, 79% and histidine 0.66%. Steamed gourami has an intact appearance and is pale white in color. The aroma of steamed gourami is fresh and tasty according to the specific gourami. The texture of the meat is dense, soft and very compact. The taste of steamed gourami is savory according to the specific type.

Physicochemical properties and consumer acceptance of sodium-reduced condiment from fermented horse gram (Macrotyloma uniflorum)

Excessive dietary salt intake is associated with the development of hypertension, causing millions of deaths around the world annually. Meanwhile, food insecurity caused by rapid growth of global population has drawn researchers’ interest in exploiting underutilized legumes as food resources. Hence, the aim of this study was to develop a novel sodium-reduced condiment from a neglected legume, horse gram (Macrotyloma uniflorum). Different formulations of fermented horse gram condiment (FHGC) were developed by gradual reduction of NaCl content. Nutritional composition and quality parameters of FHGC were assessed in present study. The results showed that amino acid nitrogen content and free amino acid content were both inversely related to NaCl concentration of FHGC. Sensory test conducted revealed that FHGC-12 had the highest consumer acceptability. However, penalty analysis suggested that saltiness was a less significant factor in affecting consumer liking of FHGC. Optimizing the balance of umami, sweet and bitter taste amino acids, in conjunction with NaCl is crucial in affecting acceptability of FHGC, rather than having the highest quantity ratio of amino acids. Therefore, it is imperative to maintain a well-balanced ratio of these key taste components to enhance consumer acceptance of FHGC.

Composition of Flavour Non Volatile Compound Steamed Milkfish (Chanos chanos)

The purpose of this study is to identify the composition of non-volatile flavor compounds contained in steamed milkfish (Chanos chanos). This study was carried out at the Fisheries Product Processing Laboratory, Faculty of Fisheries and Marine Sciences, Padjadjaran University, Jatinangor; IPB Integrated Laboratory. The study was conducted experimentally by treating a sample of 100 grams of steamed milkfish (at 100°C for ± 30 minutes) to identify non-volatile compounds and 1 milkfish to test the description. Product description tests were carried out on samples which included appearance, flesh, aroma, texture, and taste. High Performance Liquid Chromatography (HPLC) was used to identify non-volatile flavour compounds. The findings revealed that steamed milkfish had 15 non-volatile flavor compounds identified from 15 amino acid compounds. The two umami-flavoring amino acids are 3.21% glutamic acid and 2.14% aspartic acid. The four sweet tasting amino acids are 1.31% alanine, 0.96% threonine, 1.13% glycine and 0.72% serine. The nine bitter amino acids are lysine 2.15%, leucine 1.74%, arginine 1.32%, valine 1.26%, isoleucine 1.16%, phenylalanine 0.95%, tyrosine 0.79%, methionine 0. .69% and 0.90% histidine. Steamed milkfish has a whole appearance with a bright yellowish color. The savory aroma of fresh steamed milkfish is in accordance with the characteristics of milkfish that live in brackish water. The texture of the meat is dense and very dense. The taste of savory steamed milkfish is according to its kind.

Near-infrared spectroscopy of Chinese soy sauce for quality evaluation

The feasibility of near-infrared (NIR) spectroscopy and partial least-squares regression (PLSR) was investigated for rapid prediction of the quality of Chinese soy sauce. Twenty-four soy sauce samples from eight common brands available in China were analyzed for the contents of various components that may affect the quality of soy sauce. Sensory evaluation was also conducted to determine the relationship between components and the sensory quality of soy sauce. Subsequently, NIR spectra (400–2500 nm) of the samples were obtained, and the raw spectra were subjected to different pretreatment methods. PLSR was performed on the raw and treated spectra to construct models using a calibration set. The performance of models was evaluated by comparing the determination coefficient of prediction (R2P) and root-mean-square error of prediction (RMSEP). The results showed that the models constructed using the moisture content (R2P of 0.825 and RMSEP of 1.73), amino acid nitrogen content (R2P of 0.785 and RMSEP of 0.071), and taste scores (R2P of 0.733 and RMSEP of 11.93) performed well, and the interactions between amino acid nitrogen content and taste of soy sauce were clarified. This study demonstrates that NIR spectroscopy can be used as a valid alternative method for rapid prediction of the sensory quality of soy sauce during processing.

Identification of the flavor profiles of Chinese pancakes from various areas using smart instruments combined with E-noses and E-tongues

In order to reveal the flavor characteristics of Chinese pancakes, the aroma and taste compounds of seven traditional Chinese pancakes were identified. The results showed that electronic nose (E-nose) analysis with PCA could successfully distinguish the aroma profiles of seven Chinese pancakes; the principal components PC1 and PC2 represented 75.74% and 23.2% of the total variance (98.94%) respectively. Meanwhile, the discrimination index of taste profiles of seven Chinese pancakes based on electronic tongue (E-tongue) analysis with LDA was 99.32%; the discriminant factors DF1 and DF2 represented 94.99% and 4.33% of the total variance respectively. Furthermore, GC-MS results demonstrated that thirty-three flavor compounds were identified in seven Chinese pancakes, including aldehydes, alcohols, alkanes, acids, and aromatics. Among the flavor components, aldehydes with ROAVs higher than 1 contributed most significantly to the overall aroma, such as (E,E)-2,4-nonadienal present the largest contribution in Qingzhou pancake, Jinan and Yishui pancake; hexanal present the largest contribution in Shenxian and Gaomi pancake; nonanal and benzeneacetaldehyde present the largest contribution in Linqu and Tai’an pancake, respectively. The umami and sweet taste amino acids were the most abundant in all the Chinese pancake samples, and Qingzhou pancake had relatively high amino acid content. The content of glucose was higher than maltose in Gaomi, Shenxian, and Tai’an pancakes, whereas the content of maltose was higher than glucose in Linqu, Qingzhou, Jinan, and Yishui pancakes. These results indicated that the aroma and taste profiles of Chinese pancakes differed significantly in terms of their flavor compound composition. The presented results could be beneficial for providing a comprehensive method for flavor profile identification of traditional whole-grain-based staples such as Chinese pancakes. Keywords: Chinese pancake, flavor profile, E-nose, E-tongue, smart instrument, identification DOI: 10.25165/j.ijabe.20231601.6817 Citation: Liu W, Fan Y, Liu Q N, Xu F, Zhang L, Hu H H. Identification of flavor profiles of Chinese pancakes from various areas using smart instruments combined with E-noses and E-tongues. Int J Agric & Biol Eng, 2023; 16(1): 283–290.

Effects of Drying Methods on Taste Components and Flavor Characterization of Cordyceps militaris.

The influences of four drying methods (hot air drying (HAD), vacuum freeze drying (VFD), vacuum drying (VD) and intermittent microwave combined with hot air drying (MW-HAD)) on the taste profile and flavor characteristic of Cordyceps militaris were investigated. MW-HAD samples had the highest levels of umami taste 5'-nucleotides, bitter taste amino acids, and equivalent umami concentration (EUC) value. The aroma fingerprints and differences of dried Cordyceps militaris were established by GC-MS with odor activity values (OAVs) and GC-IMS with principal component analysis (PCA). GC-MS data showed that the predominant volatiles of dried samples were aldehydes, alcohols, and ketones. VFD samples had the highest amount of total aroma compounds and C8 compounds. Moreover, 21 aroma-active components (OAVs ≥ 1) were the main contributors to the flavor of dried Cordyceps militaris. The OAVs of 1-octen-3-one and 3-octanone associated with mushroom-like odor in VFD were significantly higher than other samples. Furthermore, a significant difference in flavor compounds of four dried samples was also clearly demonstrated by GC-IMS analysis with PCA. GC-IMS analysis revealed that VFD samples had the most abundant flavor compounds. Overall, MW-HAD was an effective drying method to promote umami taste, and VFD could superiorly preserve volatiles and characteristic aroma compounds in dried Cordyceps militaris.

Taste Characteristics of Various Amino Acid Derivatives.

Amino acids contribute to the taste of foods. Previous studies on the taste of amino acids focused mainly on α-amino acids, and therefore, the taste characteristics of amino acid derivatives remain unclear. In the present study, we targeted 6 different amino acid derivatives, β-alanine, citrulline, creatine, γ-aminobutyric acid, taurine, and ornithine, and evaluated their taste characteristics in a human sensory study. All tested amino acid derivatives showed multiple taste qualities; no derivatives had only a single taste quality. However, their taste intensities were relatively weak even at high concentrations. Given that the interactions between amino acid derivatives and nucleotide result in taste enhancements, we investigated the effect of inosine 5'-monophosphate (IMP) on the taste characteristics and found that the taste intensity of ornithine increased in the presence of IMP. This finding will be useful for understanding the role of amino acid derivatives as taste substances in daily foods.

Effects of Pretreatment on the Volatile Composition, Amino Acid, and Fatty Acid Content of Oat Bran.

Pretreatment improves the edible quality of oat bran and prolongs the shelf life, whereas the effect of pretreatments (i.e., steaming(S-OB), microwaving(M-OB), and hot-air drying(HA-OB)) on the flavor characteristics of oat bran is unknown. This study identified volatile composition using HS-SPME/GC–MS and an electronic nose of oat bran. The amino acid compositions were determined by a High-Speed automatic amino acid analyzer and the fatty acids were determined by gas chromatography. The results showed that steaming and microwaving pretreatments enhanced the nutty notes of oat bran. Sixty-four volatile compounds in four oat brans were identified. OB exhibited higher aroma-active compounds, followed by S-OB, and M-OB, and the HA-OB had the lowest aroma-active compounds. Hexanal, nonanal, (E)-2-octenal,1-octen-3-ol, 2-ethylhexan-1-ol, and 2-pentylfuran were the key volatile compositions in oat bran. The aldehyde content decreased and the esters and ketones increased in steamed oat bran. Microwaving and hot air drying increased the aldehyde content and decreased the ester and alcohol content. Steamed oat bran had the lowest levels of total amino acids (33.54 g/100 g) and bitter taste amino acids (5.66 g/100 g). However, steaming caused a significant reduction in saturated fatty acid content (18.56%) and an increase in unsaturated fatty acid content (79.60%) of oat bran (p < 0.05). Hot air drying did not result in an improvement in aroma. The results indicated that steaming was an effective drying method to improve the flavor quality of oat bran.

국내육성 차 품종별 홍차의 유효성분과 품질 특성 비교

This study was conducted to obtain basic data for the oxidated characteristics of tea cultivars in Korea. In particular, three kinds of cultivated green teas of Korea, namely Chamnok, Keumsull, and Beachwisull, were oxidized by the traditional sunburn Jaeksal method of Hadong area, Korea, and the oxidized teas were analyzed for their free amino acid content, taste, and aroma. When compared with landrace, a traditional tea cultivar of Korea, and used as a control in this study, the theaflavin content of the three kinds of teas in this study was higher, but their caffeine and free amino acid contents were lower. Furthermore, the total catechin content was the highest in Beachwisull (3.04 %) and the lowest in Chamnok (0.18 %). Likewise, the theaflavin content was the highest in Chamnok (0.54 %). Finally, astringency and taste after astringency were most significant in Beachwisull, and greenishness was the highest in Keumsull.

Influences of Aging Methods and Temperature on Meat Quality of Pork Belly from Purebred Berkshire and Crossbred Landrace×Yorkshire×Duroc (LYD) Pigs

We studied effects of aging methods and temperature on the physical, chemical, and amino acid composition of pork belly from Berkshire and Landrace× Yorkshire×Duroc (LYD) swine. Pork belly samples were assigned randomly to breed groups (Berkshire and LYD), aging temperature groups (0°C and 9°C), and aging method groups. One samples of vacuum-packaged hanging pork bellies were hung in a refrigerated cooler with 83±2.0% humidity, while the other samples were immersed in a 3.5% salt solution in a vacuum package and subsequently stored in the same cooler for 2 weeks. LYD pork had lower pH and purge loss and higher lightness values than those of Berkshire pork (p<0.05). Moreover, thiobarbituric acid reactive substances and hardness values of LYD pork were lower than those of Berkshire pork after aging (p<0.05). Berkshire pork had a higher level of flavorful amino acids than LYD pork did during aging (p<0.05). Bellies aged at elevated temperatures for two weeks had higher volatile basic nitrogen. However, significantly higher percentages of flavorful and sweet taste amino acids were observed in bellies aged at 9°C compared to those aged at 0°C for 2 weeks. Moisture content was higher in immersed samples than hanging samples after two weeks of aging (p<0.05). Hanging pork bellies exhibited higher texture profiles than immersed pork bellies at two weeks (p<0.05). We concluded that breeds, aging temperature, and methods affected most quality attributes of pork belly.