Changes in the total phenolic contents, chlorogenic acid, and caffeine of coffee cups regarding different brewing methods

A long extraction time for traditional cold coffee brewing considerably reduces the production efficiency of this type of beverage. Herein, a new ultrasound-assisted cold brewing (UAC) method was established. The feasibility of UAC was assessed by comparison with main physicochemical characteristics, non-volatile and volatile compounds in coffee extracts produced by hot brewing and conventional static cold brewing methods. Compared to the static cold brews, the levels of total dissolved solids, total lipids, proteins, and titrated acids of UAC coffee extracts increased by 6–26%, 10–21%, 26–31%, and 12–15%, respectively. Caffeine, chlorogenic acid, and trigonelline concentrations were also determined by HPLC. Based on the volatile profiles obtained by HS-SPME-GC/MS, the aroma compounds in UAC was significantly different (p < 0.05) from hot brews but similar to static cold ones, suggesting that ultrasonication compensated for the time of the static cold brewing, thereby considerably shortening the extraction time (1 h vs. 12 h). This work demonstrated that the combination of ultrasound-assisted with cold brew could produce coffee with good flavor and increase the extraction efficiency, which may provide an option for the acceleration of the cold brew coffee process.

Chemical and sensory evaluation of cold brew coffees using different roasting profiles and brewing methods

Cascara, the dried husk of coffee cherries, has attracted attention as a potential beverage due to its unique flavour profile and potential health benefits. Traditionally, cascara is prepared using hot brewing methods. However, recent interest in cold brewing methods has led to research on how temperature affects the functional properties of cascara beverages. Colour (CIE L*a*b*), total dissolved solids and titratable acidity were determined in cascara beverages prepared at 5, 10, 15 and 20 °C. The concentration of phenols and flavonoids, as well as antioxidant properties were evaluated using spectrophotometric methods. Caffeine, chlorogenic acid and melanoidins were quantified by HPLC. The mineral composition was determined using inductively coupled plasma mass spectrometry (ICP-MS). The results were compared with a hot-brewed cascara beverage. Cold brewing resulted in significantly higher concentrations of total phenolic compounds, expressed as gallic acid equivalents (ranging from 309 to 354 mg/L), total flavonoids, expressed as quercetin equivalents (11.8-13.6 mg/L), and caffeine (123-136 mg/L) than the hot-brewed cascara beverage sample (p<0.05). Temperature had a noticeable effect on most variables, although the effect appeared to be random. In particular, concentrations of caffeine (p<0.01) and copper (p<0.001) were highest in beverages prepared at 20 °C and decreased with decreasing brewing temperature. Multivariate analysis showed that minerals (As, Co, Mn, Sn, Mg and Ca), hue and phenolic concentration contributed to the first principal component, which mainly differentiated the hot-brewed sample. Antioxidant-related variables, total titratable acidity and Se contributed most to the second principal component, which facilitated the separation of samples brewed at 5 °C. To our knowledge, this is the first study to suggest that temperature affects the functional properties of cascara beverage produced by the cold brewing method. Experimental evidence supports the existence of a direct proportionality between caffeine and copper concentrations and brewing temperature.

Recently, a new trend called cold brewing gained popularity in the tea and coffee beverage industry. Cold brew and hot brew black tea may have different sensory qualities and antioxidant levels because of their polyphenolic properties and brewing processes. The objectives of this study were to determine antioxidant properties and polyphenolic content of commercial brands of cold brew and hot brew black tea. The total phenolic content of the cold brew tea was determined to be 0.19 mg/mL gallic acid equivalents/100 g and hot brew tea was 0.43 mg/mL gallic acid equivalents/100 g when assayed by Folin-Ciocalteu&amp;rsquo;s reagent method. The total flavonoid content of the cold brew tea was 0.40 mg/mL catechin equivalents/100 g and hot brew was 1.01 mg/mL catechin equivalents/100 g. Moreover, antioxidant capacity of cold brew and hot brew black tea was analyzed where their ability to scavenge DPPH radicals was 86.3% and 88.1% respectively. There was a significant difference in total phenolic content between hot brew and cold brew (p = 0.004). Similarly, there was a significant difference in total flavonoid between cold brew and hot brew (p = 0.004). Additionally, there was a significant difference in DPPH scavenging activity between cold brew and hot brew (p = 0.016). Overall, it can be concluded that although cold brew tea contained a lower amount of phenolics and flavonoids as compared to hot brew tea, they both were able to scavenge DPPH radicals in nearly same capacity.

Cold brewing coffee has gained increasing popularity as a novel brewing method. A completely different flavour profile during cold brewing extraction (smooth and mild) is a result of the low-energy process, prolonged water-grind contact times and long preparation time. The aim of our research was to compare coffee drinks obtained with an innovative device for a faster, dynamic cold coffee extraction process (Hardtank) to drinks prepared traditionally in 24 h and hot brewed drinks. This study investigated the differences in chemical composition (volatile, non-volatile and lipid compounds), sensory properties and antioxidant capacity of coffee drinks from various extraction processes carried out at variable brewing temperatures, times and percolation modes. The results showed that the new cold maceration technique using coffee bed percolation (Hardtank) improved the quality of cold coffee drinks, making them similar in taste to hot coffee drinks. Among the studied extractions, the combination of a lower temperature (19.3 °C) and percolation process appeared to be the ideal setting for the most efficient extraction of compounds such as chlorogenic acids, gallic acid, caffeine, trigonelline, 5-(hydroxymethyl)furfural and lipids and consequently for their intake. In addition, FTIR spectra indicated an even 4 times greater quantity of lipids in Hardtank drinks than in classic cold brew and up to 5 times more lipids than in hot brew coffee, which contribute to the formation of the aroma and flavour. The decreased extraction time and use of coffee bed percolation could be beneficial for the quality and taste of cold brew products.

The acidity and antioxidant activity of cold brew coffee were investigated using light roast coffees from Brazil, two regions of Ethiopia, Columbia, Myanmar, and Mexico. The concentrations of three caffeoylquinic acid (CQA) isomers were also determined. Cold brew coffee chemistry was compared to that of hot brew coffee prepared with the same grind-to-coffee ratio. The pH values of the cold and hot brew samples were found to be comparable, ranging from 4.85 to 5.13. The hot brew coffees were found to have higher concentrations of total titratable acids, as well as higher antioxidant activity, than that of their cold brew counterparts. It was also noted that both the concentration of total titratable acids and antioxidant activity correlated poorly with total CQA concentration in hot brew coffee. This work suggests that the hot brew method tends to extract more non-deprotonated acids than the cold brew method. These acids may be responsible for the higher antioxidant activities observed in the hot brew coffee samples.

Coffee is one of the most popular beverages which are rich in sensory attributes. What is the best time for brewing coffee after roasting is important question for consumer. In general, people do not directly brew coffee that has just been roasted. The chemical change which causes sensory changes still continues during the resting time. Enjoying coffee is about taste, everyone has different preferences. Some people prefer bitter coffee; some people like the sour taste and some others consume sweet coffee. Therefore, information about sensory and chemical profile is needed to give several options for consumer to choose their brewing method and brewing time before the coffee has decreased in sensory quality. This current study aims to know sensory and chemical changes of cold and hot brew Arabica coffee at various resting time. The materials were coffee beans Arabica Jawa Gunung Halu obtained from Cibeber, Sidangkerta Village, Mekarsari District, Bandung Regency, West Java. The roasted bean stored at various resting time (1, 3, 5, 7, and 9 days) than brewed in cold and hot brew methods. Sensory evaluation was conducted by 10 trained panelists using quantitative descriptive analysis (QDA). Furthermore, chemical analyses which were evaluated consist of the value of pH, brix and Total Dissolved Solid (TDS). The results showed that longer resting time followed by sensory characteristics changes on aroma, after taste, sweetness that is in line with chemical attributes change in Brix. Moreover color change in line with TDS change. While the different brewing techniques show that hot brew has higher value than cold brew in most all of parameters except Brix value. Keywords — chemical, coffee, panelists , resting time, sensory

Differences in brewing methods both from extraction time and brewing water temperature can affect the number of chemical compounds dissolved. This study applied the cold brew brewing method with high-speed stirring to Arabica Semendo coffee with extraction times of 15, 30, and 45 minutes at different particle sizes of coffee powder (coarse, medium, and fine) to obtain coffee with better characteristics than the commonly used brewing methods (hot brew and cold brew) and acceptable in sensory evaluation. The pH, viscosity, total soluble solids, total microbes, and sensory evaluation by hedonic tests on taste, color, and aroma were investigated. Coffee with high-speed stirred cold brewing for more than 30 minutes with finer coffee grounds had higher pH, viscosity, and total soluble solids than common brewing as a control. The size of the coffee grounds and the difference in brewing method did not affect microbial contamination. The results of the hedonic test on color, taste, and aroma in the cold brewing method of high-speed stirring produced coffee that was accepted by consumers and was not significantly different from the common brew.

Purpose: This work aimed to conduct chemical characterization, assess antioxidant activity, and quantify phenolic compounds in Amazonian Robusta Coffee beverages prepared using diverse roasting degrees and extraction methods. Theoretical Framework: Coffee is globally consumed and holds substantial importance as a commodity. Its chemical composition and biological activity of coffee are influenced by several factors, such as cultivar, roasting degree and brewing method. Methods: Amazonian Robusta Coffee beverages were prepared using diverse roasting degrees and extraction methods (Hario V60, French press and Cold Brew). Characterization was conducted to physicochemical analysis (color parameters, browning index, pH, Brix and total dissolved solids), total phenolic compounds (Folin-Ciocalteu method) and antioxidant activity (FRAP, DPPH, ABTS+ and ORAC assays). Results and Conclusions: Hario V60 beverage demonstrated the highest levels of total phenolic compounds (+50%) and antioxidant activity (+40%) across all roast levels (p&lt;0.01), with significantly increased concentrations of total dissolved solids and phenolic compounds compared to French Press and Cold Brew. This enhanced extraction efficiency is likely due to greater surface area exposure and the percolation method. In contrast, Cold Brew exhibited higher a*, b* and Browning Index values (p&lt;0.05), indicating more intense colors from prolonged extraction and greater melanoidin solubilization. Research Implications: This work showed the chemical composition and antioxidant activity of Amazonian Robusta coffee beverages and their potential application for sustainable production. Originality/Value: No previous study has assessed the antioxidant potential, phenolic content and physicochemical characterization of Amazonian Robusta coffee beverages.

Specialty and regular coffee bean quality for cold and hot brewing: Evaluation of sensory profile and physicochemical characteristics

Optimization of microwave-assisted extraction of phenolic compounds from tomato: Characterization by FTIR and HPLC and comparison with conventional solvent extraction

Nanotechnology has become increasingly important in modern society, and nanoparticles are routinely used in many areas of technology, industry, and commercial products. Many species of nanoparticle (NP) are typically synthesized using toxic or hazardous chemicals, making these methods less environmentally friendly. Consequently, there has been growing interest in green synthesis methods, which avoid unnecessary exposure to toxic chemicals and reduce harmful waste. Synthesis methods which utilize food waste products are particularly attractive because they add value and a secondary use for material which would otherwise be disposed of. Here, we show that spent coffee grounds (SCGs) that have already been used once in coffee brewing can be easily used to synthesize gold and silver NPs. SCGs derived from medium and dark roasts of the same bean source were acquired after brewing coffee by hot brew, cold brew, and espresso techniques. The total antioxidant activity (TAC) and total caffeoylquinic acid (CQA) of the aqueous SCG extracts were investigated, showing that hot brew SCGs had the highest CQA and TAC levels, while espresso SCGs had the lowest. SCG extract proved effective as a reducing agent in synthesizing gold and silver NPs regardless of roast or initial brew method.

European countries have recently started experimenting with growing and producing their own teas in small quantities, mainly for the specialty tea sector. To characterize European teas, this study investigated a set of five tea types obtained from different Camellia sinensis varieties/cultivars, representing various oxidation grades (green, white, yellow, oolong, black), all grown and processed in the only tea garden in Europe (in Germany) that focuses on all five types. Hot and cold brews were studied by measuring the total phenolic (TPC) and flavonoid contents (TFC), the antioxidant capacity and UV-Vis spectra, also with the objective of discriminating between the different tea types and the different plant varieties. The dried leaves were analyzed to measure the content of essential and toxic elements and by ATR-FTIR spectroscopy to determine a chemical fingerprint for identifying the tea varieties and types. The average levels of TPC (hot brew = 5.82 ± 2.06; cold brew = 5.4 ± 2.46 mM GAEq), TFC (hot brew = 0.87 ± 0.309; cold brew = 0.87 ± 0.413 mM CAEq), and antioxidant capacity (ORAC assay-hot brew = 20.9 ± 605; cold brew = 21.8 ± 8.0 mM TXEq, ABTS assay-hot brew = 15.2 ± 5.09; cold brew = 15.1 ± 5.8 mM TXEq, FRAP assay-hot brew = 9.2 ± 3.84; cold brew = 10.4 ± 5.23 mM AAEq) observed compared well with those from other parts of the world such as China, Africa, and Taiwan. The hazard quotient <1 and the hazard index of 0.14 indicate that there is no non-carcinogenic risk from consumption of these teas. The obtained information is essential for elucidating the characteristics and the impact of tea processing and tea variety on the health benefits of these tea products coming from a single European tea garden. This multifaceted approach would help tea growers in Europe increase their knowledge on the health attributes of the teas they grow, ultimately leading to optimization of the nutraceutical properties of these teas.

Tea is one of the plantation crops which contributes to 3.27% of the Gross Domestic Product (GDP) in Indonesia. As one of Indonesia’s export commodities, tea plays a big role in foreign exchange revenue. Among various kinds of processed tea drinks, 14.36% of tea consumers in Indonesia have a preference for consuming ready-to-drink (RTD) tea, implying its market potential in Indonesia. Furthermore, the increasing trend of healthy products resulted in the rise of the probiotic beverage market globally. Therefore, an RTD tea product with the addition of Lactobacillus plantarum Dad-13 has been developed, named ProbioTea. This study discusses the development of the ProbioTea product and vulnerability analysis of the two processes used: cold brew and hot brew. The study aimed to determine the level of vulnerability at each stage of ProbioTea manufacturing to reduce the risk of failure in large-scale production. This study also investigated antioxidant contents, cell viability, pH, and the visual appearance of ProbioTea. The result showed that the mixing and storage process has a high vulnerability to both cold and hot brew methods. The result of the assessment of risk vulnerability in the ProbioTea production process showed no risk with an extreme level of vulnerability. Thus, it indicated that the risk in the ProbioTea production process can be managed properly. The percentage of antioxidants in the cold brewing method was 51.25 - 71.76%, while the hot brewing method shows 44.89 - 54.74%. After storage, ProbioTea with the cold brew method experienced an increase in antioxidants because the low temperature was able to protect the bioactive compounds in tea. Meanwhile, there was no significant difference in the cell viability of ProbioTea processed on the cold and hot brew. After storage, the cell viability contained in ProbioTea was more than 6.8 CFU/mL. The acidity of ProbioTea processed in both cold and hot brew was not significantly different. This research concluded that the ProbioTea product is good.

The total phenolic content and antioxidant activities of the organic spent coffee ground obtained from different brewing methods were investigated. Among various brewing methods, the organic spent coffee ground showed the highest total phenolic content (TPC) and antioxidant activities and was selected as raw material for extracting phytochemicals using ultrasound assisted extraction (UAE) with different temperature, time, and solvent ratios. In terms of extraction time, the TPC and antioxidant activities were continuously increased until the extraction time reached to 40 min and then dramatically decreased indicating the appropriate extraction time. The extract with highest TPC (78.85 mg garlic acid equivalent/ml antioxidant crude extracts) and antioxidant activities was obtained when extracted with UAE at 50 °C, solvent ratios of 1:20 g/ml and 40 min. The assays of 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2’-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ATBS) and ferric reducing antioxidant power (FRAP) were detected at 717.11 µM Trolox/antioxidant crude extracts, 711.23 µM Trolox/antioxidant crude extracts, and 2401.90 µM Ammonium ferrous sulfate/antioxidant crude extracts, respectively. When applied the antioxidant crude extracts from organic cold brew spent coffee ground into low fat pork sausage at 1.00%, the improvement of TPC and antioxidant activities was obtained. After storage for 14 days, the TPC and DPPH scavenging activity was increased to 18.07 mg garlic acid equivalent/100 g pork sausage and 159.76 µM Trolox/100 g pork sausage, respectively, while the 2‐thiobarbituric acid reactive substance values were reduced to 9.18 g malondialdehyde/100 g pork sausage. The rancidity of the sausage was ceased, and the shelf-life was prolonged when the extract was added.