A comprehensive sensory evaluation of beers from the Chinese market

Extrusion of casein and whey protein isolate enhances anti-hardening and performance in high-protein nutrition bars

Model high-protein nutrition bars (HPNBs) were formulated by incorporating whey protein isolate (WPI) and casein (CN) at various extrusion temperatures (50, 75, 100, 125, and 150 °C) with a protein content of 45 g per 100 g. The free sulfhydryl groups, amino groups, hardness, and microstructures of HPNBs were analyzed periodically at 37 °C over a storage period of 45 days. Specifically, sulfhydryl group, amino group and surface hydrophobicity of extruded whey protein isolate (WPE) and extruded casein (CE) were significantly reduced (P < 0.05) compared to those of unextruded protein. HPNBs formulated with WPE (HWPE) and CE (HWCE) exhibited a slower hardening rate compared to those formulated with unmodified protein. Moreover, the color difference, hardness and sensory score of HPNBs after 45 days of storage were used as indicators, and the results of the TOPSIS multiple index analysis indicated that HPNB formulated with WPI extruded at 150 °C possessed the best quality characteristics.

Brewing a Craft Belgian-Style Pale Ale Using Pichia kudriavzevii 4A as a Starter Culture

There is an expanding market for beer of different flavors. This study aimed to prepare a craft Belgian-style pale ale with a non-Saccharomyces yeast. Pichia kudriavzevii 4A was used as a sole starter culture, and malted barley as the only substrate. The ingredients and brewing process were carefully monitored to ensure the quality and innocuousness of the beverage. During fermentation, the yeast consumed 89.7% of total sugars and produced 13.8% v/v of ethanol. The product was fermented and then aged for 8 days, adjusted to 5% v/v alcohol, and analyzed. There were no traces of mycotoxins, lead, arsenic, methanol, or microbiological contamination that would compromise consumer health. According to the physicochemical analysis, the final ethanol concentration (5.2% v/v) and other characteristics complied with national and international guidelines. The ethyl acetate and isoamyl alcohol present are known to confer sweet and fruity flavors. The sensory test defined the beverage as refreshing and as having an apple and pear flavor, a banana aroma, and a good level of bitterness. The judges preferred it over a commercial reference sample of Belgian-style pale ale made from S. cerevisiae. Hence, P. kudriavzevii 4A has the potential for use in the beer industry.

Mapping the Sensory Fingerprint of Swedish Beer Market through Text and Data Mining and Multivariate Strategies

The continuous increase of online data with consumers’ and experts’ reviews and preferences is a potential tool for sensory characterization. The present work aims to overview the Swedish beer market and understand the sensory fingerprint of Swedish beers based on text data extracted from the Swedish alcohol retail monopoly (Systembolaget) website. Different multivariate strategies such as heatmaps, correspondence analysis and hierarchical cluster analysis were used to understand the sensory space of the different beer styles. Additionally, sensory space for specific hop cultivars was also investigated. Results highlighted Gothenburg as the main producing area in Sweden. The style Indian Pale Ale (IPA) is the largest available at the retail monopoly. From a sensory perspective, commonalities and differences were found between beer types and styles. Based on the aroma description, different types of ale and lager can cluster together (such as Porter and Stout and Dark lagers). Additionally, an associative relationship between specific aromas and hop cultivars from text data information was successfully achieved.

Physiological and transcriptional responses of Phalaris arundinacea under waterlogging conditions

As a high-yielding forage grass, Phalaris arundinacea widely distributed in the Qinghai-Tibet Plateau region of China. To explore physiological and molecular response mechanism of Phalaris arundinacea under waterlogging, we analyzed the biomass and physiological indexes of three locally grown strains under the submerged condition of 10 cm. The material Z0611 showed the strongest waterlogging resistance while the YS showed the weakest performance. Transcriptome sequencing analysis demonstrated that the YS and Z0611 had 17010 and 7566 differently expression genes (DEGs), respectively, which were mainly concentrated in the metabolic process, cell, ribosome, phenylpropanoid biosynthesis pathway in GO and KEGG databases. We also identified a large number of genes involved in carbohydrate metabolism, hormone signaling regulation, transcription factors, antioxidant system, and ethylene signaling. Our research may provide a scientific basis for the restoration of wetland environment on the Qinghai-Tibet Plateau, and lay a foundation for further exploration of the waterlogging resistance genes of Phalaris arundinacea and breeding of new strains resistant with waterlogging stress.

Impact of germination on the chemical profile of HomChaiya rice wort and beer

HomChaiya rice is one of the important rice varieties in Thailand. However, the commercial value of this rice is very limited as it is not widely known and has limited availability. The present research aimed to produce an alcoholic beverage from malted HomChaiya rice, and various chemical profiles (physicochemical, phytochemicals, volatiles, and amino acids) were studied. HomChaiya rice was germinated for different periods (3, 5, and 7 days), kilned at 60 °C, and used to produce wort and beer. Physicochemical qualities such as pH, brix, titratable acidity, viscosity, soluble nitrogen, FAN, and extractability were higher in the wort, and the results were significantly influenced by the germination time. On the other hand, the color values were higher in the beer samples, and prolonged germination brightened the beer color. The total phenolic content, flavonoid content, and various antioxidant potentials (DPPH, ABTS, and reducing power) were significantly increased in the beer samples when made with rice malt germinated for 7 days compared to the wort under similar conditions. Wort samples had 13 identified volatiles, whereas the beer samples had 30 volatile compounds. Furthermore, 20 amino acids were identified, and most of them were found at a higher level in the wort samples compared to beer samples, and prolonged germination slightly increased the amino acid levels. The beer samples' sensory characteristics showed that the HomChaiya rice germination period had no significant effect.

An alcoholic beverage from malted HomChaiya rice was produced and various chemical profiles and sensory characteristics were studied.

Milk Source Identification and Milk Quality Estimation Using an Electronic Nose and Machine Learning Techniques

In this study, an electronic nose (E-nose) consisting of seven metal oxide semiconductor sensors is developed to identify milk sources (dairy farms) and to estimate the content of milk fat and protein which are the indicators of milk quality. The developed E-nose is a low cost and non-destructive device. For milk source identification, the features based on milk odor features from E-nose, composition features (Dairy Herd Improvement, DHI analytical data) from DHI analysis and fusion features are analyzed by principal component analysis (PCA) and linear discriminant analysis (LDA) for dimension reduction and then three machine learning algorithms, logistic regression (LR), support vector machine (SVM), and random forest (RF), are used to construct the classification model of milk source (dairy farm) identification. The results show that the SVM model based on the fusion features after LDA has the best performance with the accuracy of 95%. Estimation model of the content of milk fat and protein from E-nose features using gradient boosting decision tree (GBDT), extreme gradient boosting (XGBoost), and random forest (RF) are constructed. The results show that the RF models give the best performance (R² = 0.9399 for milk fat; R² = 0.9301 for milk protein) and indicate that the proposed method in this study can improve the estimation accuracy of milk fat and protein, which provides a technical basis for predicting the quality of milk.

Comparison of sensory and chemical evaluation of lager beer aroma by gas chromatography and gas chromatography/mass spectrometry

BACKGROUND

Although the evaluation of beer is conducted by sensory experts, we cannot neglect the influence of human factors and subjectivity. This problem could be solved by the chemical analysis of the volatile part of beer aroma and, from this, we can build a database for the construction of a model that classifies samples in a comparable manner to sensory assessment.

RESULTS

Twenty-two batches of the same beer brand were assessed by sensory evaluation and described chemically in terms of the contents of alcohols and esters (n = 9), hop essential oil compounds (n = 15) using gas chromatography (GC) and other aroma volatiles (n = 33) as analysed by head space solid-phase microextraction (SPME)-GC/mass spectrometry. The best match of 91% with respect to sample classification on the basis of chemical analyses to sensory scores was achieved with a dataset of results from headspace-SPME and analyses of higher alcohols and esters by regularized discriminant analysis.

CONCLUSION

The results of the present study show that deviations in beer aroma are not a consequence of a permanent repeatable error in brewing process, nor are they influenced by raw materials, but, instead, they are a consequence of alcoholic fermentation. Sensory analysis could be replaced with chemical/statistical analysis on an appropriate data set and for a distinct beer brand. The good results achieved confirm our approach; however, for different beer brands or types, this method should be optimised. © 2017 Society of Chemical Industry.

Multiple-sip temporal dominance of sensations associated with acceptance test: a study on special beers

In this study, we proposed the use of a multiple-sip temporal dominance of sensations (TDS) test alongside with an acceptance test over repeated consumption for the analysis of special beers, with the aim of contributing to a deeper understanding of consumer behavior regarding temporal descriptions and sensory acceptance. Consumers of special beers sequentially evaluated six sips of a particular type of beer by TDS analysis and an acceptance test was performed for each sip. Four different kinds of specialty beers were evaluated [Bohemian Pilsner (BP), Witbier (WB), Belgian Strong Ale Dubbel (BD), and Russian Imperial Stout (RS)]. In general, the descriptive profile of beers varied temporally, i.e., there was an increased dominance of bitterness and a decreased dominance of fruity, floral, toffee, and coffee attributes. Concurrently, a reduction in sensory acceptance with an increased number of sips, especially the last sip, was observed in two kinds of beers that possessed a strong flavor, BD and RS. BP and WB presented smooth attributes and low notable characteristics, which could have contributed to the maintenance of the acceptance grades as the number of sips increased. The combination of TDS and acceptance over repeated sips can be useful for obtaining detailed descriptions of products that are closer to real time consumption by consumers, and thus aids in ensuring good product performance once released. The information obtained can also help product development scientists to fine-tune product formulations and ensure acceptability.