Key Odorants in Japanese Roasted Barley Tea (Mugi-Cha)-Differences between Roasted Barley Tea Prepared from Naked Barley and Roasted Barley Tea Prepared from Hulled Barley

Effects of roasting and steeping on nutrients and physiochemical compounds in organically grown naked barley teas

Barley tea, a popular beverage with cultural traditions in East Asia, has long been esteemed for its flavor, aroma, thirst-quenching properties and perceived health benefits attributed to bioactive compounds. This study investigated the nutritional, bioactive, and antioxidant aspects of three commercial naked barley varieties, focusing on the impact of roasting and subsequent steeping for tea. Roasting did not affect total dietary fiber or β-glucan content. The process reduced sugar content and led to the disappearance of free amino acids, contributing to high levels of acrylamide and color changes. Roasting diminished total phenolic compounds, particularly flavonoids, resulting in reduced antioxidant activity. Metabolite analysis identified compounds in roasted grains that could influence tea flavor and aroma. Roasted barley tea made from these varieties was not a source of dietary fiber or antioxidants, but also contained no acrylamide. Therefore, consumers seeking such benefits from barley are urged to consume whole grain foods.

Analysis of mousy off-flavor compound 2-Acetyl-tetrahydropyridine using Liquid Chromatography Mass Spectrometry with Electrospray Ionization in sour beer

Mousy off-flavor describes N-heterocycles compounds related to spoilage in the brewing industry. It has also been identified in sour beers through sensory analysis. Therefore, preventing spoilage N-heterocycles development is essential to preserve end-products and obviate economic losses. To this day, no methods or protocols have been reported to identifying mousy off-flavor compounds in a beer matrix. The main objective of this work was to develop a standardized quantification method for 2-acetyl-3,4,5,6-tetrahydropyridine (ATHP) in beer matrix, by Liquid Chromatography Mass Spectrometry with Electrospray Ionization (LC-MS-ESI). Extraction of ATHP in the samples was performed using QuEChERS (quick, easy, cheap, effective, rugged, and safe) technique. Over a dozen different potentially mousy cask-aged sour beers including other spontaneously fermented beverages were provided, based on sensory analysis, to determine the variation in ATHP levels. Results indicated ATHP was found in all the samples, ranging from 1.64 ± 0.06 to 57.96 ± 2.15 µg L-1. Herein, we described our detection method of mousy-off flavor compounds which enables future research to mitigate the occurrence of such defects in fermented beverages matrix.•ATHP content in samples varied from 1.64 ± 0.06 to 57.96 ± 2.15 µg L-1.•The recovery range of ATHP using LC-MS-ESI varied from 71% to 97%.•Basified QuEChERS salting-out procedure is applicable for ATHP extraction from beer and other fermented beverages matrices.

Check-all-that-apply (CATA)- and rate-all-that-apply (RATA)-based sensometric assessment of germinated-wheat beverages

Sensometrics assesses sensory perspectives in consumer research using statistics and various methodologies. This study evaluated consumer responses to hot and cold germinated-wheat beverages in check-all-that-apply (CATA) and rate-all-that-apply (RATA) assessments using sensometric statistical approaches, including Cochran's Q test, penalty-lift analysis, and multiple factor analysis. Hot beverages (HB) were prepared by infusion using different amounts of germinated wheat (HB_1: 0.8 g/100 mL, HB_2: 2 g/100 mL, and HB_3: 4 g/100 mL), while cold beverages (CB) were made using cooled boiled germinated wheat with varying concentrations (CB_1: 25 g/L, CB_2: 50 g/L, and CB_3: 75 g/L). Results of the CATA study suggested that consumers preferred HB_1 and CB_1 because they expressed the sensory characteristics associated with liking, including "barley tea flavor", "neat taste", and "nutty taste", while "bitterish taste", "stuffy taste", and "astringent taste" were undesirable attributes. "Browning index", "barley tea odor", and "nutty taste" showed significant differences (p < 0.05) in both favorable and unfavorable rating scores. Overall, CB_1 elicited a clear taste and odor with fewer negative emotions. These findings demonstrate the usefulness of the sensometric approach combined with CATA and RATA analyses to obtain more easily interpretable results on the sensory perception of consumers to new food products.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-023-05884-z.

A Review of N-Heterocycles: Mousy Off-Flavor in Sour Beer

Beer has over 600 flavor compounds and creates a positive tasting experience with acceptable sensory properties, which are essential for the best consumer experience. Spontaneous and mixed-culture fermentation beers, generally classified as sour beers, are gaining popularity compared to typical lager or ale styles, which have dominated in the USA for the last few decades. Unique and acceptable flavor compounds characterize sour beers, but some unfavorable aspects appear in conjunction. One such unfavorable flavor is called "mousy". This description is usually labeled as an unpleasant odor, identifying spoilage of fermented food and beverages. It is related as having the odor of mouse urine, cereal, corn tortilla chips, or freshly baked sour bread. The main compounds responsible for it are N-heterocyclic compounds: 2-acetyltetrahydropyridine, 2-acetyl-1-pyrroline, and 2-ethyltetrahydropyridine. The most common beverages associated with mousy off-flavor are identified in wines, sour beers, other grain-based beverages, and kombucha, which may contain heterofermentative lactic acid bacteria, acetic acid bacteria, and/or yeast/fungus cultures. In particular, the fungal species Brettanomyces bruxellensis are associated with mousy-off flavor occurrence in fermented beverages matrices. However, many factors for N-heterocycle formation are not well-understood. Currently, the research and development of mixed-cultured beer and non/low alcohol beverages (NABLAB) has increased to obtain the highest quality, sensory, functionality, and most notably safety standards, and also to meet consumers' demand for a balanced sourness in these beverages. This paper introduces mousy off-flavor expression in beers and beverages, which occurs in spontaneous or mixed-culture fermentations, with a focus on sour beers due to common inconsistency aspects in fermentation. We discuss and suggest possible pathways of mousy off-flavor development in the beer matrix, which also apply to other fermented beverages, including non/low alcohol drinks, e.g., kombucha and low/nonalcohol beers. Some precautions and modifications may prevent the occurrence of these off-flavor compounds in the beverage matrix: improving raw material quality, adjusting brewing processes, and using specific strains of yeast and bacteria that are less likely to produce the off-flavor. Conceivably, it is clear that spontaneous and mixed culture fermentation is gaining popularity in industrial, craft, and home brewing. The review discusses important elements to identify and understand metabolic pathways, following the prevention of spoilage targeted to off-flavor compounds development in beers and NABLABs.

The characteristic of the key aroma-active components in white tea using GC-TOF-MS and GC-olfactometry combined with sensory-directed flavor analysis

BACKGROUND

White tea has become more and more popular with consumers due to its health benefits and unique flavor. However, the key aroma-active compounds of white tea during the aging process are still unclear. Thus, the key aroma-active compounds of white tea during the aging process were investigated using gas chromatography-time-of-flight-mass spectrometry (GC-TOF-MS) and gas chromatography-olfactometry (GC-O) combined with sensory-directed flavor analysis.

RESULTS

A total of 127 volatile compounds were identified from white tea samples with different aging years by GC-TOF-MS. Fifty-eight aroma-active compounds were then determined by GC-O, and 19 of them were further selected as the key aroma-active compounds based on modified frequency (MF) and odor activity value (OAV).

CONCLUSION

Aroma recombination and omission testing confirmed that 1-octen-3-ol, linalool, phenethyl alcohol, geraniol, (E)-β-ionone, α-ionone, hexanal, phenylacetaldehyde, nonanal, (E, Z)-(2,6)-nonadienal, safranal, γ-nonalactone and 2-amylfuran were the common key aroma-active compounds to all samples. Cedrol, linalool oxide II and methyl salicylate were confirmed peculiar in new white tea, while β-damascenone and jasmone were peculiar in aged white tea. This work will offer support for further studies on the material basis of flavor formation of white tea. © 2023 Society of Chemical Industry.

Analysis of Volatile Profile and Aromatic Characteristics of Raw Pu-erh Tea during Storage Based on GC-MS and Odor Activity Value

Volatile constituents are critical to the flavor of tea, but their changes in raw Pu-erh tea (RAPT) during storage have not been clearly understood. This work aimed to investigate the volatile composition and their changes at various storage durations. The volatile profile of RAPT was determined using headspace solid-phase microextraction in combination gas chromatography-mass spectrometry. A total of 130 volatile compounds were identified in RAPT samples, and 64 of them were shared by all samples. The aroma attributes of RAPT over a storage period ranging from 0 to 10 years were assessed through the combination of odor activity value (OAV), aroma characteristic influence(ACI) value, and multivariate statistical analysis. The results revealed that RAPT exhibited a distinct floral and fruity aroma profile after storage for approximately 3-4 years. A notable shift in aroma was observed after 3-4 years of storage, indicating a significant turning point. Furthermore, the likely notable shift after 10 years of storage may signify the second turning point. According to the odor activity value (OAV ≥ 100), eight key volatile compounds were identified: linalool, α-terpineol, geraniol, trans-β-ionone, α-ionone, (E,E)-2,4-heptadienal, 1-octanol, and octanal. Combining OAV (≥100) and ACI (≥1), five compounds, namely linalool, (E,E)-2,4-heptadienal, (Z)-3-hexen-1-ol, 2,6,10,10-tetramethyl-1-oxaspiro [4.5]dec-6-ene, and octanal, were identified as significant contributors to the aroma. The results offer a scientific foundation and valuable insights for understanding the volatile composition of RAPT and their changes during storage.

Flavor perception and health benefits of tea

As one of the most consumed non-alcoholic beverages in the world, tea is acclaimed for its pleasant flavor and various health benefits. Different types of tea present a distinctive flavor and bioactivity due to the changes in the composition and proportion of respective compounds. This article aimed to provide a more comprehensive understanding of tea flavor (including aroma and taste) and the character of tea in preventing and alleviating diseases. The recent advanced modern analytical techniques for revealing flavor components in tea, including enrichment, identification, quantitation, statistics, and sensory evaluation methodologies, were summarized in the following content. Besides, the role of tea in anti-cancer, preventing cardiovascular disease and metabolic syndrome, anti-aging and neuroprotection, and regulating gut microbiota was also listed in this article. Moreover, questions and outlooks were mentioned to objectify tea products' flavor quality and health benefits on a molecular level and significantly promote our understanding of the comprehensive value of tea as a satisfactory health beverage in the future.

Unraveling the role of germination days on the aroma variations of roasted barley malts via gas chromatography-mass spectrometry based untargeted and targeted flavoromics

Roasting imparts malts with an increased amount of hedonic aromas. However, the relationship between the production of roasted malts and the generation of characteristic malt aromas remains unclear. In this study, roasted barley malts (RM) were prepared from three consecutive germination days (3, 4, 5D), and the aroma profiles among RM and base malt were holistically compared via HS-SPME-GC-MS/O-based flavoromics. Furthermore, the wort color, free amino acids, reducing sugars, and fatty acids compositions were determined before-and-after roasting. Results showed that roasting could flatten variations of precursors regardless of germination days. Additionally, based on quantitation of 53 aromas, a PLS-DA model was applied to differentiate all malts by 17 aromas with VIP ≥ 1. As for aroma harmony, RM with 4D-germination outstood due to a pleasant nutty note with the highest sweet-to-nutty index of 0.8. This work answers how germination days would impact the aroma of RM for the first time.

A comprehensive review on functional beverages from cereal grains-characterization of nutraceutical potential, processing technologies and product types

Due to growing consumer interest in fitness and wellbeing, foods and beverages with therapeutic and functional qualities are in higher demand. In addition to being significant staple crops and major providers of nutrition and energy, cereals are rich in bioactive phytochemicals with health benefits. Cereal grains offer a lot of promise for processing into functional beverages since these include a wide variety of bioactive phytochemicals such as phenolic compounds, carotenoids, dietary fibres, phytosterols, tocols, gamma-oryzanol, and phytic acid. Despite the fact that a wide variety of beverages made from cereal grains are produced globally, they have received very little technological and scientific attention. The beverages confer replacements for milk made from cereal grains, roasted cereal grain teas and fermented non-alcoholic cereal grain drinks. This review emphasizes on the three primary kinds of functional beverages made from cereal grains. Further, the potential applications and directions for the future related to these beverages are discussed with elaborated processing methods, health benefits and product attributes. Cereal grain-based beverages may represent a promising new class of healthy functional beverages in our daily lives as the food industry gets more diverse.

Study on the Changes in Volatile Flavor Compounds in Whole Highland Barley Flour during Accelerated Storage after Different Processing Methods

The effect of heat processing on the flavor characteristics of highland barley flour (HBF) in storage was revealed by analyzing differences in volatile compounds associated with flavor deterioration in HBF using GC-MS identification and relative odor activity values (ROAVs). Hydrocarbons were the most abundant in untreated and extrusion puffed HBFs, while heterocycles were found to be the most abundant in explosion puffed, baked, and fried HBFs. The major contributors to the deterioration of flavor in different HBFs were hexanal, hexanoic acid, 2-pentylfuran, 1-pentanol, pentanal, 1-octen-3-ol, octanal, 2-butyl-2-octanal, and (E,E)-2,4-decadienal. Amino acid and fatty acid metabolism was ascribed to the main formation pathways of these compounds. Baking slowed down the flavor deterioration in HBF, while extrusion puffing accelerated the flavor deterioration in HBF. The screened key compounds could predict the quality of HBF. This study provides a theoretical basis for the regulation of the flavor quality of barley and its products.

Insights into the Key Odorants in Large-Leaf Yellow Tea (Camellia sinensis) by Application of the Sensomics Approach

Large-leaf yellow tea (LYT) is a yellow tea product with a specific aroma characteristic and is enjoyed with increasing enthusiasm in China. However, its key odorants are still unknown. In this study, 46 odorants in the headspace and vacuum-distillate of the tea infusion were identified via aroma extract dilution analysis. Sixteen compounds were newly found in LYT infusion. They were present in the highest flavor dilution factors together with 2-ethyl-3,5-dimethylpyrazine. All odorants were quantitated to evaluate their own odor activity values (OAVs). High OAVs were found for 2-methylbutanal (malty, 210), (E,E)-2,4-heptandienal (fatty/flowery, 170), 2-methylpropanal (malty, 120) and 2,3-diethyl-5-methylpyrazine (earthy/roasty, 110). An aroma recombinate consisting of 17 odorants (all OAVs ≥ 1) in an odorless nonvolatile LYT matrix mimicked the overall aroma of the original infusion, verifying the successful characterization of key aroma components in a LYT beverage. The knowledge of key odorants obtained showed potential for simplifying industrial flavor optimization of the LYT product.

Molecular Rearrangement of Four Typical Grape Free Terpenes in the Wine Environment

In order to analyze the molecular rearrangement of terpenes in wine during aging, the changes in linalool, α-terpineol, nerol, and geraniol in model wine were investigated in the dark at low temperature for 90 days. Headspace-gas chromatograph-mass spectrometer/olfactometry was used for qualitative and relative quantitation of terpenes. Quantum mechanical calculation was used to analyze the Gibbs free energy. The results showed that nerol was converted into d-limonene, terpinolene, linalool, and α-terpineol. Geraniol was converted into β-ocimene, terpinolene, and linalool. Linalool was converted into terpinolene. The conversion rate of nerol to terpinolene was the highest with 5.94%. α-Terpineol was not converted spontaneously into other terpenes due to its lowest Gibbs free energy, indicating that the cyclization and isomerization could occur spontaneously through an exotherm reaction. However, the dehydroxylation of linalool, nerol, and geraniol required an energy source.

Highland Barley Tea Polyphenols Extract Alleviates Skeletal Muscle Fibrosis in Mice by Reducing Oxidative Stress, Inflammation, and Cell Senescence

The tea of roasted Highland barley is a cereal-based drink rich in polyphenols. A model of skeletal muscle senescence and fibrosis was constructed using d-galactose-induced C2C12 myotubes, and Highland barley tea Polyphenols (HBP) were extracted for the intervention. We found that HBP effectively alleviated oxidative stress, inflammation, and fibrosis induced by d-galactose-induced skeletal muscle senescence. Also, HBP treatment significantly down-regulated pro-fibrotic genes, inflammation, and oxidative stress levels in a contusion model of senescent mice. Reduced levels of SIRT3 protein was found to be an essential factor in skeletal muscle senescence and fibrosis in both cellular and animal models, while HBP treatment significantly increased SIRT3 protein levels and viability in skeletal muscle. The ability of HBP to mitigate skeletal muscle fibrosis and oxidative stress was significantly reduced after SIRT3 silencing. Together, these results suggest that HBP intervention can significantly alleviate aging-induced oxidative stress, inflammation, and skeletal muscle fibrosis, with the activation of SIRT3 as the underlying mechanism of action.

Barley in the Production of Cereal-Based Products

Barley (Hordeum vulgare L.) is unjustly neglected today as a food grain. Interest in the use of barley in the food industry has increased recently. The reason for this is its content of dietary fibre, especially β-glucan, which has been shown to reduce blood cholesterol and lower blood sugar levels. The main nutritional components of barley and barley products, besides the mentioned β-glucan, are starch, sugar, proteins, fat and ash. Although not common in the production of bakery products, barley can be very easily involved in the production of the same products, and such products have improved nutritional characteristics and acceptable sensory characteristics, which make them desirable. Barley has great potential for use in a wide range of cereal-based foods as a partial or full replacement for currently used grains (such as wheat, oats, rice and corn). This article provides basic and general information about the use of barley in food and the processing of barley grains for use in the manufacturing of cereal-based products, with particular attention to the use of barley in the manufacturing of bread (flatbread and leavened bread), noodles and pasta, muffins and cakes and cookies and biscuits.

Simultaneous component analysis as an interesting preliminary data analysis method in GC-MS – An example of headspace screening of Polish grasses

70 species of grasses family (Poaceae), coming from genera: Agrostis, Alopecurus, Anthoxanthum, Apera, Arrhenatherum, Avena, Brachypodium, Briza, Bromus, Calamagrostis, Corynephorus, Cynosurus, Dactylis, Danthonia, Deschampsia, Digitaria, Echinochloa, Elymus, Eragrostis, Festuca, Glyceria, Helictotrichon, Hierochloe, Holcus, Hordeum, Koeleria, Leymus, Lolium, Milium, Molinia, Nardus, Panicum, Phalaris, Phleum, Phragmites, Poa, Saccharum and Setaria, collected mostly from natural stands in Poland during 2020 season, were subjected to GC-MS fingerprinting of headspace volatile fraction above dried material. Obtained mass spectrometry data were analyzed by means of principal component analysis (PCA) and hierarchical cluster analysis (HCA). Five species: Glyceria maxima (Hartm.) Holmb., Lolium multiflorum Lam., Hordeum jubatum L., Bromus tectorum L. and Bromus secalinus L. were identified as outliers, which is consistent with our earlier analysis by thin layer chromatography. These species deserve further look and their outliance is orthogonal to coumarin content, which was independently observed for odorant species of grasses.

Clinical cross-reactivity of wheat and barley in children with wheat allergy

BACKGROUND

Several studies have reported in vitro cross-reactivity between wheat and barley. However, evidence regarding the clinical cross-reactivity of wheat and barley is limited. This study examined the clinical cross-reactivity of barley and wheat among children with immediate-type wheat allergies.

METHODS

We examined the threshold dose of a wheat oral food challenge for wheat-allergic children. We examined the reactivity of barley, and the oral food challenges of barley tea and barley rice were implemented as needed. We measured the specific immunoglobulin E (sIgE) levels in wheat, ω-5 gliadin, and barley.

RESULTS

We evaluated 53 children (39 [74%] boys) with a median age of 6.6 years. Among them, 39 (74%) patients had a history of anaphylaxis to wheat. The median wheat-, barley-, and ω-5 gliadin-sIgE levels were 57.3, 12.1, and 3.2 kU_A /L, respectively. Twelve patients reacted to barley tea (1.8 mg), 14 reacted to barley rice (220-440 mg), and 27 were tolerant to barley tea and barley rice. Barley-allergic patients had significantly higher wheat- and ω-5 gliadin- and barley-sIgE levels and significantly lower threshold doses of wheat than barley-tolerant patients. Omega-5 gliadin-sIgE was the most useful predictor of barley allergy among wheat-allergic patients; the ω-5 gliadin-sIgE 95% positive predictive value for barley allergy was 4.6 kU_A /L.

CONCLUSIONS

Half of wheat-allergic children reacted to barley. A lower threshold dose of wheat is related to cross-reactive barley allergies. Omega-5 gliadin-sIgE predicts cross-reactive barley allergy in children allergic to wheat. Clinical cross-reactivity to barley should be considered in the management of wheat-allergic children.

Characterization of Bitter Compounds in Shaoxing Huangjiu by Quantitative Measurements, Taste Recombination, and Omission Experiments

Excessive and uncoordinated bitterness of Shaoxing Huangjiu, a traditional Chinese rice wine, reduces its acceptance by consumers. To determine the compounds responsible for this bitterness, gas chromatography-mass spectrometry and high-performance liquid chromatography were performed on four types of Shaoxing Huangjiu (Yuanhong, Huadiao, Shanniang, and Xiangxue wine) for targeted quantitation of candidate compounds known to contribute to bitterness. Calculations of dose-over-threshold factors revealed that isoamyl alcohol, 1-hexanol, phenylethanol, ethyl butyrate, ethyl lactate, furfural, histidine, and arginine were important bitter compounds. Taste recombination experiments demonstrated that a recombination model constructed using the screened known bitter compounds showed good similarity with the original sample in bitter taste. Furthermore, omission experiments revealed that isobutanol, isoamyl alcohol, 1-hexanol, phenylethanol, ethyl acetate, ethyl butyrate, ethyl lactate, furfural, arginine, and valine were the compounds affecting the bitter taste perception. This study provides a certain guiding effect on the bitterness control and taste improvement of Shaoxing Huangjiu.

Flavor of tea (Camellia sinensis): A review on odorants and analytical techniques

Tea is among the most consumed nonalcoholic beverages worldwide. Understanding tea flavor, in terms of both sensory aspects and chemical properties, is essential for manufacturers and consumers to maintain high quality of tea products and to correctly distinguish acceptable or unacceptable products. This article gives a comprehensive review on the aroma and off-flavor characteristics associated with 184 odorants. Although many efforts have been made toward the characterization of flavor compounds in different types of tea, modern flavor analytical techniques that affect the results of flavor analysis have not been compared and summarized systematically up to now. Thus, the overview mainly provides the instrumental flavor analytical techniques for both aroma and taste of tea (i.e., extraction and enrichment, qualitative, quantitative, and chemometric approaches) as well as descriptive sensory analytical methodologies for tea, which is helpful for tea flavor researchers. Flavor developments of tea evolved toward time-saving, portability, real-time monitoring, and visualization are also prospected to get a deeper insight into the influences of different processing techniques on the formation and changes of flavor compounds, especially desired flavor compounds and off-flavor substances present at (ultra)trace amounts in tea and tea products.

Uncovering aroma boundary compositions of barley malts by untargeted and targeted flavoromics with HS-SPME-GC-MS/olfactometry

In this study, HS-SPME/GC-MS based untargeted and targeted flavoromics combing with olfactometry were employed to uncover aroma boundary compositions of five types of commercial barley malts with a wide range of Lovibond (L), including kilned base malts (1.8 L and 3.5 L) and roasted caramel malts (10 L, 60 L, and 120 L). Thirty-two compounds were identified as aroma-active with modified detection frequency (MF) > 50%. 3-Methylbutanal (malty), (2E)-nonenal (fatty, cardboard-like), and 2-furfural (burnt, bready) were recognized as the most influential odorants with MF > 70% in all the malts. After untargeted flavoromics, twenty-eight aromas were retained and quantitated. Furthermore, aroma boundary compositions inside/among malt groups were explored with PLS-DA. Eight aroma markers, 3-methylbutanal, 2-isopropyl-5-methyl-2-hexenal, (2E,4E)-Decadienal, 2-furfual, maltol, 2-acetylpyrrole, phenylacetaldehyde, and ethyl hexadecanoate were shortlisted for aroma boundary compositions regarding to the Lovibond of malts.

Characterization of the key aroma-active compounds in high-grade Dianhong tea using GC-MS and GC-O combined with sensory-directed flavor analysis

Dianhong tea (DHT) is popular for its pleasant caramel-like aroma. In this study, the aroma profile of high-grade DHT have been studied using gas chromatography-mass spectrometry (GC-MS) and gas chromatography-olfactometry (GC-O) combined with headspace solid phase microextraction (HS-SPME). A total of 52 aroma-active compounds were identified by GC-O coupled with aroma extract dilution analysis (AEDA) and odor specific magnitude estimation (Osme). Among them, quantification of 21 aroma-active compounds indicated that the content of linalool (5928 µg/kg) was the highest in high-grade DHT, followed by phenylethanol (3923 µg/kg) and phenylacetaldehyde (1801 µg/kg). Sensory-directed aroma recombination and omission tests further verified that phenylacetaldehyde, linalool, geraniol and 3-ethyl-2,5-dimethylpyrazine were important contributors to the overall sensory characteristics of high-grade DHT which dominated mainly by floral, sweet and caramel-like odors. This work will provide a theoretical reference for comprehensively understanding the aroma characteristic of DHT.

Anti-Obesity and Anti-Adipogenic Effects of Administration of Arginyl-Fructose-Enriched Jeju Barley (Hordeum vulgare L.) Extract in C57BL/6 Mice and in 3T3-L1 Preadipocytes Models

In our previous study, we reported that arginyl-fructose (AF), one of the Amadori rearrangement compounds (ARCs) produced by the heat processing of Korean ginseng can reduce carbohydrate absorption by inhibiting intestinal carbohydrate hydrolyzing enzymes in both in vitro and in vivo animal models. This reduced absorption of carbohydrate might be helpful to control body weight gain due to excessive carbohydrate consumption and support induced calorie restriction. However, the weight management effect, except for the effect due to anti-hyperglycemic action, along with the potential mechanism of action have not yet been determined. Therefore, the efforts of this study are to investigate and understand the possible weight management effect and mechanism action of AF-enriched barley extracts (BEE). More specifically, the effect of BEE on lipid accumulation and adipogenic gene expression, body weight gain, body weight, plasma lipids, body fat mass, and lipid deposition were evaluated using C57BL/6 mice and 3T3-L1 preadipocytes models. The formation of lipid droplets in the 3T3-L1 treated with BEE (500 and 750 µg/mL) was significantly blocked (p < 0.05 and p < 0.01, respectively). Male C57BL/6 mice were fed a high-fat diet (30% fat) for 8 weeks with BEE (0.3 g/kg-body weight). Compared to the high fat diet control (HFD) group, the cells treated with BEE significantly decreased in intracellular lipid accumulation with concomitant decreases in the expression of key transcription factors, peroxisome proliferator-activated receptor gamma (PPARγ), CCAAT/enhancer-binding protein alpha (CEBP/α), the mRNA expression of downstream lipogenic target genes such as fatty acid binding protein 4 (FABP4), fatty acid synthase (FAS), and sterol regulatory element-binding protein 1c (SREBP-1c). Supplementation of BEE effectively lowered the body weight gain, visceral fat accumulation, and plasma lipid concentrations. Compared to the HFD group, BEE significantly suppressed body weight gain (16.06 ± 2.44 g vs. 9.40 ± 1.39 g, p < 0.01) and increased serum adiponectin levels, significantly, 1.6-folder higher than the control group. These results indicate that AF-enriched barley extracts may prevent diet-induced weight gain and the anti-obesity effect is mediated in part by inhibiting adipogenesis and increasing adiponectin level.

Characterization and Quantitative Comparison of Key Aroma Volatiles in Fresh and 1-Year-Stored Keemun Black Tea Infusions: Insights to Aroma Transformation during Storage

The aroma of Keemun black tea (KBT) changes during storage. We investigated key aroma volatiles of fresh KBT (FKBT) and KBT stored for 1 year. Through gas chromatography−olfactometry−mass spectrometry/aroma extract dilution analysis (GC-O-MS/AEDA), 27 aroma volatiles with a flavor dilution (FD) value ≥16 were quantitated. In odor activity value (OAV) analysis, the two samples had nearly the same key aroma volatiles; (Z)-methyl epijasmonate was the exception. Dimethyl sulfide, 3-methylbutanal, 2-methylpropanal, and linalool had especially high OAVs. Except for β-damascenone, volatiles with OAVs > 1 had higher concentrations in FKBT, which revealed that most key aroma compounds were lost during storage. Sweet, malty, floral, and green/grassy aromas corresponded directly to certain compounds. Lastly, the addition test indicated that the addition of several key aroma volatiles decreasing during storage could enhance the freshness of KBT aroma, which may be a potential to control the aroma style of KBT or other teas in industry.

Impact of Malt Extract Addition on Odorants in Wheat Bread Crust and Crumb

Application of gas chromatography-olfactometry and aroma extract dilution analysis to the volatiles isolated from (1) crust and (2) crumb of a wheat bread made with the addition of a dark liquid malt extract (LME) to the dough and (3) crust and (4) crumb of a reference bread made without addition resulted in the identification of 23 major odorants. Their quantitation followed by the calculation of odor activity values (OAV = ratio of concentration to odor threshold value) suggested that LME addition influenced the aroma of the bread predominantly by increasing seasoning-like smelling sotolon in crust and crumb, and caramel-like smelling compounds maltol and 4-hydroxy-2,5-dimethylfuran-3(2H)-one (HDMF) in the crumb. The increase in sotolon and maltol was explainable by direct transfer from the LME to the bread, whereas HDMF must have been formed from LME-derived precursors. This difference needs to be considered in the targeted optimization of LMEs for bread making.

Deciphering the Formulation Secret Underlying Chinese Huo-Clearing Herbal Drink

Herbal teas or herbal drinks are traditional beverages that are prevalent in many cultures around the world. In Traditional Chinese Medicine, an herbal drink infused with different types of medicinal plants is believed to reduce the ‘Shang Huo’, or excessive body heat, a status of sub-optimal health. Although it is widely accepted and has a very large market, the underlying science for herbal drinks remains elusive. By studying a group of herbs for drinks, including ‘Gan’ (Glycyrrhiza uralensis Fisch. Ex DC.), ‘Ju’ (Dendranthema morifolium (Ramat.) Tzvelev), ‘Bu’ (Microcos paniculata L.), ‘Jin’ (Lonicera japonica Thunb.), ‘Xia’ (Prunella vulgaris L.), and ‘Ji’ (Plumeria rubra L.), the long-term jargon is connected with the inflammation of modern immunology through a few pro-inflammatory markers. In vitro studies have indicated that cellular inflammation is lowered by Ju and Jin either individually or synergistically with Gan. Among all herbs, only Gan detoxicated cellular toxicity of Bu in a dose dependent manner. The synergistic formulation of Ju and Gan, or Jin and Gan, in a reduction of Shang Huo, was tested in vivo. Both combinations exhibited a lower percentage of neutrophils, monocytes, and CD4⁺/CD8⁺ ratio in the blood, as well as inflammatory cytokines. Furthermore, body weight in the combinatory groups was more stable than treatments using single herbs. The combination of old traditional oriental methods with Western science logistics, has resulted in the formulation of different herbs into one concoction for the use of detoxification and synergism.

Odour-active compounds in liquid malt extracts for the baking industry

An odorant screening by gas chromatography–olfactometry (GC–O) and a crude aroma extract dilution analysis (AEDA) applied to the volatiles isolated from a light and a dark liquid malt extract (LME) by solvent extraction and solvent-assisted flavour evaporation (SAFE) identified 28 odorants. Fifteen major odorants were subsequently quantitated and odour activity values (OAVs) were calculated as ratio of the concentration to the respective odour threshold value (OTV). Important odorants in the light LME included 3-(methylsulfanyl)propanal (OAV 1500), (E)-β-damascenone (OAV 430), and 4-ethenyl-2-methoxyphenol (OAV 91). In the dark LME, sotolon (OAV 780), 3-(methylsulfanyl)propanal (OAV 550), (E)-β-damascenone (OAV 410), acetic acid (OAV 160), and maltol (OAV 120) were of particular importance. To get an insight into the changes during malt extract production, the quantitations were extended to the malt used as the starting material for both LMEs. Addition of a minor amount of water to malt before volatile extraction was shown to be effective to cover the free as well as the bound malt odorants. Results showed that some LME odorants originated from the starting material whereas others were formed during processing. Important process-induced LME odorants included (E)-β-damascenone and 4-ethenyl-2-methoxyphenol in the light LME as well as maltol, sotolon, (E)-β-damascenone, and 2-methoxyphenol in the dark LME. In summary, the odorant formation during LME production was shown to be more important than the transfer of odorants from the malt.

Cereal grain-based functional beverages: from cereal grain bioactive phytochemicals to beverage processing technologies, health benefits and product features

Increased consumer awareness of health and wellness has promoted a high demand for foods and beverages with functional and therapeutic properties. Cereals, apart from being important staple crops and primary sources of energy and nutrition, are replete with bioactive phytochemicals with health properties. Cereal grains contain a diverse range of bioactive phytochemicals including phenolic compounds, dietary fibers, carotenoids, tocols, phytosterols, γ-oryzanol, and phytic acid and therefore have great potential for processing into functional beverages. Although there are a variety of cereal grain-based beverages produced world-wide, very little scientific and technological attention has been paid to them. In this review, we have discussed cereal grain-based functional beverages based on 3 main categories: cereal grain-based milk alternatives, roasted cereal grain teas, fermented nonalcoholic cereal grain beverages. The processing techniques, health properties and product features of these beverages are elaborated, and the challenges and future perspectives are proposed. As the food market becomes increasingly diverse, cereal grain-based beverages could be a promising new category of health functional beverages in our daily life.