Roast Degree Research Articles

Textural properties and consumer preference of functional milk puddings fortified with apricot kernel extracts.

Both the demand for functional foods and their consumption have increased rapidly in recent years. Apricot kernels, originated in China, are rich in dietary protein, fat, fiber, and exhibit high antimicrobial and antioxidant activities. The effects of the agar-gelatin ratio and milk volume on the texture of apricot kernel milk puddings were evaluated. Texture profile analysis indicated that increasing volumes of agar and milk contributed to the hardness and gumminess but reduced the cohesiveness of puddings. The pudding sample S2 (250 ml of milk, 200 ml of water, 60 g of raw apricot kernels, 30 g of sugar, 5g of gelatin, and 2g of agar) was ultimately determined as the essential texture matrix prototype for further development of puddings. The effects of the ratio of raw apricot kernels to roasted apricot kernels and cream content in puddings on consumer preference were determined by quantitative descriptive analysis and consumer testing. Both quantitative descriptive analysis and external preference mapping of all puddings (12 samples) indicated that the pudding sample P6 (250 ml of milk, 200 ml of water, 40 g of raw apricot kernels, 20 g of roasted apricot kernels, 40 g of cream, 30 g of sugar, 5g of gelatin, and 2g of agar) showed enhanced consumer acceptance. The properties driving preference for P6 were oral smoothness, overall flavor, degree of roast, and milky taste. P6 was ultimately selected as the prototype to incorporate apricot kernels for the development of functional milk puddings with fortified essential nutrients.

Quantification of Caffeine and Chlorogenic Acid in Green and Roasted Coffee Samples Using HPLC-DAD and Evaluation of the Effect of Degree of Roasting on Their Levels.

Chlorogenic acid and caffeine are among the important components in coffee beans, determining the taste and aroma. In addition, phenols and antioxidants content possess vital health values. The main aim of this study is to determine the levels of caffeine and chlorogenic acid in several coffee samples of different origins and degrees of roasting. The coffee samples were extracted using hot water. The levels of caffeine and chlorogenic acid were quantified using high-performance liquid chromatography (HPLC) equipped with a diode array detector, a reverse phase system, and an ODS column (C18). Total phenol and antioxidant contents were previously determined for the same samples. The results showed that the highest content of caffeine was found in the medium roasted coffee (203.63 mg/L), and the highest content of chlorogenic acid content was found in the green coffee (543.23 mg/L). The results demonstrated a negative correlation between the chlorogenic acid levels with the degree of roasting, while it showed a positive correlation between the caffeine levels with the degree of roasting till a certain point where the levels dropped in the dark roasted coffee. The origin of coffee samples did not show any effect on any of the measured variables. Antioxidant effects of coffee samples were largely determined by chlorogenic acid content.

The Analysis of Chlorogenic Acid and Caffeine Content and Its Correlation with Coffee Bean Color under Different Roasting Degree and Sources of Coffee (Coffea arabica Typica)

Coffee is one of the main economic crops in the world and is now widely grown throughout Taiwan. The process of roasting coffee begins with the heating and smooth expansion of raw beans, which leads to changes in appearance and color while affecting the flavor and taste of coffee. So far, most coffee manufacturers have used visual inspection or colorimeter methods to identify differences in coffee quality. Moreover, there is no literature discussing the correlation of roasted bean color with caffeine and chlorogenic acid content. Therefore, the purpose of this experiment was to analyze the chlorogenic acid and caffeine content and their correlation with bean color under different roasting degrees and from different sources to establish basic data for the rapid identification of coffee quality in the future. In this experiment, the coffee Coffea arabica typica from Dongshan, Gukeng, and Sumatra’s Indonesian rainforest was used, and the beans were roasted into four degrees: raw bean, light, medium, and dark roast, to investigate the appearance of the coffee beans and its correlation with caffeine and chlorogenic acid content. The results showed that with a higher roasting degree, caffeine content increased gradually, except for Indonesian beans, but the chlorogenic acid content in all samples showed a declining trend with the increase in roasting degree. The correlation between the chlorogenic acid content and the color space value of the coffee bean color shows that L*, a*, and h° in both ground and unground coffee are highly correlated. The C* value of the ground and unground coffee showed a correlation coefficient of r = 0.159 ns and 0.299 ns, respectively. The correlation between the caffeine content and the color space value of the unground coffee bean shows that the a*, b*, and C* value is highly correlated with the caffeine content. The color space values of ground coffee beans show no correlation with caffeine.

Flavan-3-ols Monomer and Oligomer, and Flavor Profiles of Chocolates Produced from Fermented Cocoa Beans under Different Roasting Degree in Taiwan

Taiwan cocoa beans were fermented in a wooden box by natural occurring microorganisms for seven days. Six types of chocolate were manufactured from the fermented cocoa beans under different roasting degree. The fermentation parameters including the count of microorganisms, fermenting mass temperature, pH value of the pulp and cotyledons of cocoa bean along with the fermentation time were determined. Furthermore, the flavan-3-ols monomer and oligomer (FMO) of chocolates were determined by normal phase HPLC and the volatile aroma compounds of the six types of chocolate were analyzed by electronic nose to identify the important flavors and odors. Primary component analysis (PCA) was performed to distinguish the flavor profiles among the chocolates. The sensory assessment was conducted to evaluate the organoleptic properties of the six types of chocolate and their overall acceptability. The results showed that the total amount of FMO and proanthocyanidins in the chocolate both decrease with the intensity of the roasting degree of cocoa beans. Twenty-three important volatile aroma compounds were identified by electronic nose analysis. Differences in the amount of each compound were determined in the investigated chocolate and these are expected to cause sensory differences among the six types of chocolate. As a result, chocolates produced from beans under medium roasting condition (130°C and 25min) rated the highest score of overall acceptability among the chocolates. It was significantly higher than those of chocolate produced from light roasting beans. On the other hand, chocolate produced from cocoa bean under light roasting degree was retained more content of the bioactive compounds and could be a potent candidate of health functional food. PCA was successful to discriminate the flavor profiles of the six types of chocolate produced from beans under different roasting degree and could be used as a tool to recognize the origin of chocolate product. These results of this study could provide an important approach for producing chocolate products with desired flavor properties and bioactive compounds that have positive benefits for human health.

Influence of Various Factors on Caffeine Content in Coffee Brews.

Coffee brews are one of the most popular drinks. They are consumed for caffeine and its stimulant properties. The study aimed to summarize data on the influence of various factors on caffeine content in brews prepared with different methods. The study was carried out using a literature review from 2010–2020. PubMed and Google Scholar databases were searched. Data on caffeine content was collected by analyzing the following factors: the influence of species, brewing time, water temperature, pressure, degree of roast, grinding degree, water type, water/coffee ratio as well as other factors (such as geographical origin). To sum up, converting caffeine content to 1 L of the brew, the highest content is that of brews prepared in an espresso machine (portafilter), with the amount of 7.5 g of a coffee blend (95% Robusta + 5% Arabica), and water (the volume of coffee brew was 25 mL) at a temperature of 92 °C and a pressure of 7 bar, but the highest content in one portion was detected in a brew of 50 g of Robusta coffee poured with 500 mL of cold water (25 °C) and boiled.

The potential of dry fermented cocoa (Theobroma cacao L.) variety Lindak bean shell treated at different degrees of roasting as a functional food

Cocoa bean shell is a waste from the chocolate processing industry that has not been used optimally and still contains 5.78% polyphenols which has potential as a source of natural antioxidant compounds. The chocolate is processed in the industry with light, medium and high roasting, based on the desired product. The purpose of this study was to determine the polyphenol content and antioxidant activity of the dry fermented cocoa shells as a result of the best degree of roasting. The research method used was an experimental method using a Randomized Block Design (RBD) with 4 treatments roasting dried fermented cocoa beans of Lindak varieties by using different degrees of roasting (Without roasting; low roasting (110°C for 35 minutes), medium roasting (140°C for 30 minutes), and high roasting (190°C for 15 minutes)) and repeated 3 times. The results showed the dry fermented cocoa shells of Lindak varieties by high roasting treatment has the best phenolic total (5.24%) and antioxidant activity (37.92 ppm).

Peningkatan Mutu dan Keekonomian Kopi Arabika Melalui Penyangraian Kompleks

<em>Quality and techno-economic improvement is important to increase export value of coffee in Indonesia. Complex roasting is one excellent method in increasing the added value of coffee, such as Coffea arabica var. Sigarar Utang which is the best coffee variety in Indonesia. The study was carried out at The Indonesian Industrial and Beverage Crops Research Institute (IIBCRI), Sukabumi, West Java, from January to November 2020 which aimed: (1) to evaluate the effect of initial temperature and roasting degree on the quality of Sigarar Utang coffee bean, and (2) to evaluate the mass balance and economic feasibility of the best roasting treatment. This study was designed in a factorial completely randomized design, using 2 factors, and 2 replications. The first factor was the initial temperature which consisted of 2 levels (185 <sup>o</sup>C dan 210 <sup>o</sup>C), and the second factor was the roasting degree which consisted of 2 levels (light-medium and medium-dark). The variables observed were the water content, ash content, bulk density, brix, titratable acidity, pH, radical scavenging (antioxidant) activity, and caffeine content. The results showed that the complex roasting method with an initial temperature of 210 <sup>o</sup>C and mild-moderate roasting degrees generated a quality of Sigarar Utang coffee originating from Gunung Putri, IIBCRI, closest to the quality I of SNI 01-3542-2004. The roasted coffee beans have a special taste (score 86.51) which is a high added value. The production economic value is feasible to be adopted by small-medium scale coffee industry.</em>

Risk assessment of coffees of different qualities and degrees of roasting

During the coffee beans roasting process, occurs the formation of polycyclic aromatic hydrocarbons, which are associated with the incidence of cancer in humans. This study aimed to evaluate the influence of coffee bean quality and roasting degree regarding mutagenicity, cytotoxicity and genotoxicity. Six samples of coffee drink made with roasted and ground Coffea arabica beans from different qualities and roast degrees were used after freeze-drying. Both commercial and special quality grains suffered light, medium and dark roasting. According to the Salmonella/microsome assay, the highest concentration of commercial grain sample (dark roast) significantly increased the number of revertants of the TA98 strain in the absence of metabolization. All the samples induced cytotoxicity to HepG2 cells. These effects can be ranked in the following order from most to least toxic: medium roast – special grain > light roast – special grain > dark roast – commercial grain > dark roast – special grain > light roast – commercial grain > medium roast – commercial grain. None of the samples induced genotoxicity in HepG2 cells. Our findings show that the harmful effects of coffee depend not only on the degree of roasting but also on the grain quality.

Effect of roast degree, preparation method, and variety in the sensory and chemical characteristics of coffee (coffea arabica): A mid-infrared spectrum analysis

Effect of roast degree, preparation method, and variety in the sensory and chemical characteristics of coffee (coffea arabica): A mid-infrared spectrum analysis

Effect of preparation method and roasting temperature on total polyphenol content in coffee beverages

We evaluated the differences in total polyphenol content (TPC) of beverages prepared by three methods (Hario V60, espresso and pour-over coffee) using single-origin beans roasted at four temperatures. The beans were roasted based on the degree of roasting: the lightest roasting had a final temperature of 204 °C (first roasting), a slightly darker roasting had a final temperature of 205 °C (second roasting), a dark roasting had a final temperature of 215 °C (third roasting) and the darkest roasting had a final temperature of 220 °C (fourth roasting). TPC in the beverage was highest for the Hario V60 for all temperatures, ranging from 32.0 to 46.8 mg GAE g–1 (gallic acid equivalent per 1 g of ground beans). The third roasting had the highest TPC, ranging from 34.6 to 46.8 mg GAE g–1 for all methods of preparation, whereas the content for the fourth roasting ranged from 28.6 to 32.3 mg GAE g–1. Our results indicated that the differences in TPC in the beverage depended on the preparation method (P < 0.001) and the degree of roasting (P < 0.001). The most nutritional coffee was prepared using the Hario V60 with the third roasting.

Current Challenges of Cold Brew Coffee—Roasting, Extraction, Flavor Profile, Contamination, and Food Safety

Cold brew coffee has emerged as a new trend over the last decade. However, “cold brew” is an extraction style of ground roasted coffee with water at lower than body temperature (typically 8 °C or room temperature), rather than a beverage per se. Cold brew extraction poses several challenges, including the need for specific optimization depending on the multiple influences of coffee variety and processing, roast degree, grinding, dosage, water composition, turbulence, brew system (drip, immersion etc.), time and temperature, and their interactions. While cold brew is typically characterized by a floral sweetness, over-extraction may lead to abundant acidity and bitterness. To avoid this, an extraction degree of 70% was suggested using shorter time frames (i.e., 2 h at 15 °C with 80 g/L coffee for optimized medium roast profiles). Due to the lack of sterilizing temperatures during preparation, cold brew is significant in the coffee sector because hygiene and food safety requirements pose specific challenges. To avoid microbiological contamination and deterioration in quality, cold brew should be as freshly prepared as possible and shelf-life should be minimized.

Effects of coffee roasting technologies on cup quality and bioactive compounds of specialty coffee beans.

The effects of drum, fluidized bed, and traditional type of coffee roasting technologies on the cup quality and bioactive compounds of Yirgacheffe, Harar, and Sidama variety specialty coffee beans grown in Ethiopia were investigated at light, medium, and dark degree of roast from 150°C to 200°C for 7 to 15 min. No significant differences in cup quality were detected among the roasted coffee varieties disregard of the type of roasters. Varietal difference was found to have significant (p < .05) effect on caffeine content of the coffee beans. A significant reduction in trigonelline and total chlorogenic acids content of the coffee beans was observed during roasting process, with darker roasts attaining the least values. Drum roaster was found to be the best type of coffee roaster for specialty coffee beans at medium degree of roast with the highest cup quality, optimum bioactive compounds content, and minimum acrylamide formation. However, traditional roaster resulted at the least average cup score of 80% among the three coffee samples and the highest acrylamide content of 2.306 mg/L for Yirgacheffe coffee sample at light degree of roast. There are still some bottlenecks that need to be addressed via advancements using novel food processing technologies in order to devise the next generation of coffee processing.

A novel UHPLC method for determining the degree of coffee roasting by analysis of furans

The aim of this study was to develop a multi-analyte UHPLC method for furans and to apply it to commercial coffee samples as well as commercial roasting trials. Furans, as rising time–temperature indicators (TTIs), promised to be an alternative to unsatisfactory roasting temperature measurements. Consequently, a UHPLC–UV method for the determination of 5-hydroxymethyl-2-furfural (HMF), 5-hydroxymethyl-2-furoic acid (HMFA), 2-furfural (F), 5-methylfurfural (MF), 2-furyl methyl ketone (FMC), 2-furoic acid (FA), and for 3-caffeoylquinic acid (3-CQA) was developed and validated. Commercial roasted coffee beans contained 77.7–322 mg/kg HMF, 73.3–158 mg/kg HMFA, 109–200 mg/kg 2-F, 157–209 mg/kg MF, 12.3–32.8 mg/kg FMC, and 137–205 mg/kg FA. Roasting trial samples showed strong rising HMF contents (max.: Arabica: 769 mg/kg, Robusta: 364 mg/kg) followed by a distinct decline. Only MF and FA appeared as steady rising TTIs in the roasting process in Arabica and Robusta beans. 3-CQA fitted well as a decreasing TTI as expected.

Bioavailability and Bioactivities of Polyphenols Eco Extracts from Coffee Grounds after In Vitro Digestion.

Coffee grounds are a valuable source of bioactive compounds. In Romania, most of the amount obtained is lost through non-recovery; the rest is occasionally used as organic fertilizer. The coffee grounds were selected according to the roasting degree: blonde roasted (BR), medium roasted (MR), and dark roasted (DR). The study aimed to evaluate three extracts, obtained with a mixture of ethanol/water/acetic acid (50/49.5/0.5), depending on the roasting degree. The majority phenolic component, the antioxidant, and anti-inflammatory effect, as well as the role that gastrointestinal transit had on the bioavailability of bioactive compounds were determined. Chlorogenic acid was inversely proportional to the roasting degree. BR showed the best correlation between antioxidant and anti-inflammatory activities in vitro/in vivo. The antiproliferative capacity of the extracts determined an inhibitory effect on the tumor cells. Antimicrobial activities, relevant in the control of type 2 diabetes, were exerted through the inhibition of microbial strains (Escherichia coli). Following gastric digestion, BR demonstrated a maximum loss of 20% in the stomach. The recovery of coffee grounds depended on the pattern of functional compounds and the bioavailability of the main component, chlorogenic acid.

Sensorial Profile and Acceptability of Coffee Blends Submitted to Different Roasting Degrees

Industry of roasted and ground coffee uses Coffea arabicaL. (arabica) and Coffeacane-phora (robusta), main coffee species, to form blends consumed worldwide. In addition to blends composition, industries also vary the roast degree to attend the consumer market. Being that stated, this work aimed to evaluate the influence of roasting degree and blends composition, usingsensorial analysis, over the product acceptability. Arabica and robusta coffee were dehulled, classified, and roasted at Agtrons numbers SCAA#65 (medium-light) e SCAA#45 (moderately dark). Afterward, the authors made a preliminary test to select the blends for conventional consumers as a function of robusta coffee percentage. After the selection and determination of adequate proportion (0, 30, and 60 % m/m) of robusta coffee,the researchers invited 49 consumers to perform the tests. The researchers used preliminary tests to indicate that 29 out of the 49 consumers are capableto complete the tests. They performed the sensorial analysis of the blends, signaling grades from 1 to 9 to flavor, aroma, and appearance. Blend composition presented a higher impact over the coffee acceptability than the roast degree, in which coffee with 0% of robusta coffee, independently of the roast degree, followed by sample with 30% of robusta coffee roasted at medium light, presented the highest grades.

Effect of roasting speed on the volatile composition of coffees with different cup quality

This study investigated the volatile composition of coffee blends of different cup quality, roasted in an industrial-scale semi-fluidized bed roaster (SFBR) and in a lab-scale fluidized bed roaster (FBR), at three roasting speeds/profiles, to reach medium roast degree. Thirty volatile compounds were selectively investigated. Roasting the specialty coffee blend in both roasters produced lower concentrations of total volatile compounds, compared to the low cup quality blends. Higher concentrations of pyrazines and phenols were observed in low cup quality blends. In SFBR, quality and roasting speed affected all groups of compounds, including impact compounds such as 2,5-dimethylpyrazine, 2-ethylpyrazine, 2,3-dimethylpyrazine, 2-methoxyphenol and 4-ethyl-2-methoxyphenol. In FBR, only phenols were affected. The present results help explain why different roast profiles should be used for coffees with different cup quality for better sensory outcome and why blending should be performed after roasting of green seeds. They also show that results obtained in lab scale roasters are not necessarily reproduced in industry under the same settings.

Physiochemical Characteristics of Hot and Cold Brew Coffee Chemistry: The Effects of Roast Level and Brewing Temperature on Compound Extraction.

The role of roasting in cold brew coffee chemistry is poorly understood. The brewing temperature influences extraction processes and may have varying effects across the roast spectrum. To understand the relationship between brew temperature and roast temperature, hot and cold brew coffees were prepared from Arabica Columbian coffee beans roasted to light, medium, and dark levels. Chemical and physical parameters were measured to investigate the relationships among degree of roast, water temperature, and key characteristics of resulting coffees. Cold brew coffees showed differential extraction marked by decreased acidity, lower concentration of browned compounds, and fewer TDS indicating that cold water brewing extracts some compounds less effectively than hot water brewing. Compounds in coffee did exhibit sensitivity to degree of roast, with darker roasts resulting in decreased concentrations for both hot and cold brew coffees. Total antioxidant capacity (TAC) was only sensitive to degree of roast in cold brew coffees, while hot brew coffees had a constant TAC for all three roast levels. This indicates that the solid bean matrix and its chemical constituents interact with cold water differently than with hot water. Surface wetting, pore dynamics, and solubility all contribute to the extraction potential during brewing and are all functions of water temperature.

Sensory quality prediction of coffee assessed by physicochemical parameters and Multivariate model

Beverages from roasted coffee can be classified according to their sensory quality into Gourmet, Superior, Traditional, and not recommended for supply coffee. However, the sensory evaluation of coffee has been questioned as it can induce a subjective bias, since the assessors may be influenced by psychological, physiological, and/or emotional factors. Therefore, the aim of this study was to develop multivariate models capable of predicting the overall quality of Gourmet, Superior, and Traditional coffees, based on the physical and physicochemical parameters. For that, one hundred and eight ground roasted coffee samples were evaluated for particle size, degree of roasting, histological identification, moisture, ash, aqueous extract, soluble solids (Brix), pH, and sensory profiling. All categories presented fine grinding. No significant differences were observed for the moisture content and soluble solids (Brix) of Gourmet, Superior, Traditional, not recommended for supply coffee samples. The Traditional and not recommended for supply presented higher levels of aqueous extract, ash, and pH. A light degree of roast and higher acidity values were observed with the increase in coffee quality grades. The results of the physical and physicochemical parameters and the Principal Component Analysis allowed the separation of coffees into two classes: high-quality (Gourmet and Superior) and low-quality (Traditional and not recommended), while the one-class classification (OCC) method showed good sensitivity and was able to satisfactorily distinguish the Gourmet coffee samples from the other samples. Key words: Coffee quality; sensory; chemometrics; OCC.

Impact of Fermentation and Roasting on the Gut Health Protective Effects of Cocoa in High-Fat Diet Fed Mice

Abstract Objectives Chronic inflammation is an important driver of co-morbidities of obesity. Studies have indicated that cocoa (Theobroma cacao) and cocoa polyphenols can exert anti-inflammatory and anti-obesity properties in animal models. Fermentation and roasting are important for flavor and aroma development of cocoa but have been reported to decrease total phenolic content (TPC). The effect of these processing steps on anti-inflammatory bioactivity has not been examined in vivo. We examined the impact of fermentation and roasting on the anti-obesity and gastrointestinal protective effects of cocoa in high fat diet (HFD)-fed mice. Methods Male and female mice were fed HFD for 9 wks to induce obesity and then randomized to receive either HFD or HFD supplemented with one of seven cocoa powders (80 mg/g diet) for an additional 8 wks. The cocoa powders differed in terms of roasting (no roast or 30 min at 120°C or 170°C) and fermentation (no, cool, or hot). Body weights were measured weekly. Following euthanasia, serum and cecal digesta were collected. Visceral fat, liver, and spleen were collected and weighed. Small intestine and colon were collected and measured. Prior to euthanasia, gut permeability was measured in a subset of mice from each group. Results Mice treated with cocoa-supplemented diets had lower rate of weight gain: final body weights were 9–13% and 5–19% in males and females, respectively. Cocoa treatment also resulted in longer colon lengths (18–26% in males and 11–24% in females) and reduced gut permeability (50–75% lower) compared to HFD-fed controls indicating reduced colonic inflammation. While fermentation and roasting did impact chemistry and bioactivity, the unfermented, unroasted cocoa was not necessarily the most effective, and some combinations resulted in equivalent or improved bioactivity. Cytokine and microbial composition analysis are ongoing. Conclusions Our results show that all treatments mitigated weight gain, colon inflammation, and gut permeability induced by HFD. The degree of fermentation and roasting and TPC may not predict efficacy. This indicates that it may be possible to develop processing steps to optimize both cocoa flavor and health-related bioactivity. Funding Sources This work was funded by USDA AFRI.

Online determination of coffee roast degree toward controlling acidity

Three methods of measuring coffee roast degree were compared using titratable acidity as an indicator of roast-dependent flavor change. The first roast degree method was based on prediction of the cracks with online near infrared spectroscopy and partial least squares regression, the second was based on changes in online near infrared absorbance, and the third was the common L* value from the CIELAB color space in the visible spectrum. Roasting trials utilized arabica coffee from eight origins in an air roaster, and results demonstrated the superiority of an online near infrared sensor for real-time roast degree measurement. A second dataset with constant temperature roasts showed how acidity can be controlled by changing both the roasting temperature and roast degree, finding the linear effects of roast time and roast degree on acidity.