Effect of Temperature and Storage on Coffee's Volatile Compound Profile and Sensory Characteristics.

Meat and meat-based food produces a certain composition of volatile compounds, which can be used to identify its origin and, consequently, for food authentication. Numerous studies have explored the application of volatile compounds in identifying meat-based food using volatilomics, an emerging analytical technique. This review focuses on the volatile compound profiles, the factors influencing their production, method of extraction and detection, and their application in meat and meat-based products, with a brief discussion on their potential use for Halal authentication. The major volatile compounds associated with meat aromas include aldehydes, ketones, and alcohols, with variation in composition among different types of meat, though no definite pattern has been identified. Most of these volatile compounds are byproducts of the Maillard reaction, Strecker degradation, or interaction of both, as well as thiamine degradation. Head space-solid phase microextraction (HS-SPME) is meat's standard volatile compounds extraction method due to its convenience, solvent-free process, high sensitivity, and practicality. Gas chromatography-mass spectrometry (GC-MS) is the primary analytical technique for detecting volatile metabolites and is considered the most effective among available methods The volatilomics approach has also been applied in Halal authentication to distinguish among different animal species. The volatile compound profiles can differentiate meat-based products derived from chicken, beef, and pork. While the volatilomics approach shows great potential for use in Halal authentication, additional complementary methods are still required to obtain more comprehensive data. Keywords: Aroma, Chromatography, Halal, Identification, Vapor, Volatilomics.

Simple SummaryCheese, due to its high nutritional value, is an important element of the daily diet of many consumers. About one third of cow milk produced globally is processed into a wide assortment of cheeses. Most of them are produced on a mass scale in industrial conditions. One factor determining cheese quality is the quality of the milk it is made from. The milk of pasture-grazed cows is known to have higher content of compounds benefiting human health. Consumers are increasingly interested in artisanal products, including cheese, manufactured directly on farms or in small, local processing facilities, regarding them as natural, less processed, and free of additives. Milk for the production of this type of cheese usually comes from cows of native breeds kept on family farms. Smoking is one of the oldest traditional methods used to prolong the shelf-life of food. It imparts a pleasant aroma to cheese and improves its palatability. The literature lacks studies on the quality of smoked cheese during storage. The aim of this study is to assess changes in chemical composition and in fatty acid and volatile compound profiles during storage of smoked cheese made from the milk of native Polish cow breeds.This study investigated changes in the proximate chemical composition and profiles of fatty acids and volatile compounds of 12 smoked cheeses made from the milk of native Polish cow breeds used in Beskid Niski. Analyses were performed during the shelf life i.e., in the 1st, 21st, 42nd and 69th day of storage. Studies have shown that thanks to smoking and vacuum-packing, the chemical composition of cheese remained stable throughout the whole shelf-life. Up until the 21st day of storage, there were no statistically significant changes in the profile of fatty acids as well as volatile compounds. Changes were observed only after the mentioned storage time. After 21 days, there was a significant (p < 0.05) and steady decrease (up to day 69) in the proportion of odd-chain (by about 36%), branched-chain (by about 17%) and unsaturated fatty acids (by slightly over 1%). Among unsaturated fatty acids (p < 0.05), however, there was a significant increase in the proportion of monounsaturated fatty acids (by 5%) and a decrease in polyunsaturated fatty acids of nearly 12%. Storage lowered (by 47% in the 69th day of storage) the content of the conjugated linoleic acids (CLA), as well as lowered the n6 to n3 fatty acids ratio. During the 69 days of storage, the content of carboxylic acids increased to more than 50%. In the period from the 42nd to 69th day of cheese storage, the content of butyric acid and hexanoic acids increased twofold, whereas that of octanoic acid increased more than tenfold. Fifty-four volatile compounds were identified in the cheese. The largest group was ketones (34%), whose level decreased during storage, with 2-butanone, 3-hydroxy- (acetoin) and 2-butanone predominating. The research found that due to their low odor threshold, carboxylic acids may have negatively affected the flavor profile of the cheese.

The effects of grinding (medium-coarse) and extraction time (14–22 h) on the physicochemical and sensorial properties of cold brew coffee produced using two types of Colombian specialty coffees (Huila and Nariño) were evaluated. Cold coffee brewed under coarse grinding and 22 h of extraction exhibited the highest values of total dissolved solids, extraction yield, pH, titratable acidity (TA), and total phenolic content. The type of coffee used mainly affected the TA and pH. All cold brew coffee samples had lower TA values than their hot counterparts. Nariño cold brew samples had higher TA values than those of Huila in all treatments evaluated. Higher scores were reported in the sensorial evaluation of cold brew coffee when prepared using the shortest time (14 h) and coarse grinding for both coffee types. These coffees were characterized by strong sweetness, fruity and floral flavours, medium bitterness and acidity, and a creamy body. Furans, pyrazines, ketones, aldehydes, pyrroles, esters, lactones, furanones, and phenols were detected as odour-active compounds. The findings of this study demonstrate that the particle size, contact time, and coffee type affect the physicochemical and sensorial characteristics of cold brew coffee, leading to cold brew coffees with different flavour profiles.

Effects of different stabilization techniques on the shelf life of cold brew coffee: Chemical composition, flavor profile and microbiological analysis

In this study, the effect of chemical refining on the volatile compound and fatty acid profiles of crude fish oil is evaluated. The process mainly comprises degumming, deacidification, decoloration, and deodorization. The changes in volatile compounds during the refining process are detected by headspace solid phase micro extraction (HS‐SPME) coupled with gas chromatography‐mass spectrometry (GC‐MS). Meanwhile, the fatty acid profile is determined by GC. The results showed that hexanal, nonanal, undecanal, 2‐nonanone, and 2‐undecanone are the key volatile components of fish oil, and the relative content of each compound changed significantly in each step. The proportion of polyunsaturated fatty acids (PUFAs) in the refined oil increased, while the proportion of saturated fatty acids (SFAs) reduced significantly. This study provides a theoretical basis for the improvement of sensory characteristics of fish oil via chemical refining.Practical Applications: Chemical refining is employed for improving the characteristics of crude fish oil, mainly including the volatile compound and fatty acid compositions. The result demonstrated that the refining process could affect the volatile compound and fatty acid profiles significantly, which provided the theoretical foundation for the optimization of process conditions.An NMR‐based metabolomic approach,using “one‐to‐one” OPLS‐DA models, allows to identify biomarkers of different production zones in “Bosana” Sardinian EVOO.

Letter to the Editor: Pasteurization Temperature of Milk: A Comment on Gandy et al. (2008)

Effect of reuterin-producing Lactobacillus reuteri coupled with glycerol on the volatile fraction, odour and aroma of semi-hard ewe milk cheese

Study on ultrasound-assisted extraction of cold brew coffee using physicochemical, flavor, and sensory evaluation

This study investigated the non-volatile and volatile compounds in samples of cold brew (CB) coffee, coffee from a coffee shop (CS), ready-to-drink (RTD) coffee, and brewed coffee from a coffee maker (CM). The volatile compounds were identified using headspace solid-phase microextraction with gas chromatography-mass spectrometry, and the samples were treated with high-performance liquid chromatography for the quantification of caffeine, chlorogenic acid, and trigonelline. The results indicate that RTD coffee had the lowest amounts of non-volatile compounds. A total of 36 volatile compounds were semi-quantified; the contents of most volatile compounds in CS and Folgers samples were higher than those in CB and CM samples. The contents of 25 volatile compounds in the CM sample were higher than those in the CB sample. The consumer and instrumental data show that the bitterness intensity was correlated with pyrazines, pyrroles, and guaiacols, whereas the coffeeID intensity was correlated with phenols. Semi-quantification and principal component analysis results show that the extraction method and temperature could influence the volatile compound profiles.

Herbs, including basil, are used to enhance the flavor of food products around the world. Its potential is influenced by the quality of fresh herbs and processing practices, wherein conditions of heat treatment play an important role. The aim of the research was to determine the effect of sous-vide heat treatment on the volatile compounds profile, sensory quality, and color of basil infusions. The material used for research was aqueous basil infusion prepared conventionally at 100 °C, and using the sous-vide method (65, 75, and 85 °C). The composition of volatile compounds was identified by GC/MS analysis, the sensory profile was assessed using a group of trained panelists, while the color was instrumentally assessed in the CIE Lab system. No significant differences were found in the intensity of the taste and aroma of basil infusions at different temperatures. Seventy headspace volatile compounds were identified in the analyzed samples, ten of which exceeded 2% of relative area percentage. The most abundant compounds were eucalyptol (27.1%), trans-ocimene (11.0%), β-linalool (9.2%), and β-myrcene (6.7%). Most of the identified compounds belonged to the terpenes and alcohols groups. Our findings show that the conventional herbal infusion was more like a sous-vide infusion prepared at the lowest temperature SV65, while SV75 and SV85 were similar to each other but different from the conventional. However, a smaller number of volatile compounds in the samples heated at higher temperatures of sous-vide were identified. The sous-vide samples showed a higher content of alkanes. The sous-vide method (p ≤ 0.05) resulted in darker, less green, and less yellow basil leaves than fresh and traditionally steeped ones. Long heat treatment under vacuum at higher temperatures causes a pronounced change in the aroma composition.

Tomatoes are an important source of human health-promoting compounds, and efforts have been made to enhance their nutritional quality through conventional plant breeding or biotechnology. This study assessed the composition of volatile compounds, phenolics and carotenoids in two allele-introgressed tomato lines, an anthocyanin-rich purple tomato and a β-carotene-rich orange tomato, as well as a red tomato. The purple tomato peel accumulated a high amount of anthocyanins, mainly petunidin 3-(p-coumaroyl)-rutinoside-5-glucoside, responsible for the purple color, and other flavonoids such as rutin and kaempferol. The orange tomato did not undergo changes in the flavonoid profile but accumulated a high amount of β-carotene, with impairment on lycopene. A total of 27 volatile compounds were detected in purple tomato, 38 in orange tomato and 39 in red tomato. They comprise terpenes, carbonyls, alcohols, esters and hydrocarbons. The difference in the volatile compound profiles of ripe fruits can be related to differences in some precursor contents in the introgression lines. Orange tomato accumulates volatiles from β-carotene cleavage, not detected in the red fruits. Otherwise, volatiles from lycopene were absent in orange tomato as a result of the inhibition on lycopene accumulation. Phenolic volatiles were higher in the purple tomato, which has the highest total phenolic content. The introgessed alleles seem to have a positive effect on the enrichment of ripe tomato in bioactive compounds such as anthocyanins and β-carotene, improving nutritional quality. However, the allele introgression resulted in marked changes in volatile compound profiles, whose impact on tomato flavor and consumer acceptability needs to be evaluated. © 2019 Society of Chemical Industry.

Coffee has a complex volatile compound profile, which can be influenced by technical processes like roasting and brewing. The changes in the volatile compound profile can affect the perceived aromas. Headspace‐solid‐phase microextraction technique (HS–SPME) coupled with gas chromatography–mass spectrometry (GC–MS) and gas chromatography–olfactometry (GC–O) were used to achieve the objectives of this study: (1) to develop gas chromatography–olfactometry vocabulary for coffee brews, and (2) to analyze aroma active compound perception in differently roasted and brewed coffee. The GC–O vocabulary included 23 different aromas and 30 aroma‐active compounds. The main aroma attributes in all samples were sweet, musty, leather, skunky, burnt, and nutty. Aroma active compounds in medium roasted coffee presented floral, sweet notes, while light coffee had more nutty and roasted aroma attributes. The data from GC–MS–O suggested that roasting degree and brewing technique can influence the aroma perception of aroma active compounds. Dark roasted coffees had the least varied aroma attributes but had a higher concentration of aroma contributing compounds like 2,2′‐methylenebis‐furan (musty) and 4‐ethyl‐2‐methoxyphenol (smokey). The results also revealed that overall volatile compound composition could change the aroma perception of some coffee brew volatiles.Practical ApplicationsThe development of olfactory vocabulary and aroma active compound perception analysis can be useful for further coffee aroma analysis, characterizing volatile compound aroma changes depending on roasting and brewing technique. For the coffee industry, the olfactory vocabulary could bring an additional understanding of aroma active compound perception in differently roasted and brewed coffees.

Study of the influence of the fishing season and the storage temperature in the fishing vessel on the biogenic amine and volatile profiles in fresh yellowfin tuna (Thunnus albacares) and dry-cured mojama

Changes in the sugars and volatile compounds profiles associated with anthocyanin accumulation in oranges: Blood vs. blond varieties, and slightly pigmented vs. intensely pigmented blood fruit

Volatile fraction of DOP “Castelo Branco” cheese: Influence of breed