The effects of heating time on physical changes (weight, volume, texture and colour) of coffee beans (Outspan and Guaxupe coffee) were investigated. The roasting temperature of both samples was 170?C and samples for analysis were taken at the intervals of 7 minutes during 40 minutes of roasting. Total weight loss at the end of the roasting process was 14.43 % (light roasted) and 17.15 % (medium to dark roasted) for Outspan and Guaxupe coffee beans, respectively. Significant (P < 0.05) changes in the coffee bean breaking force values were noted between the 7th and 14th minutes, and statistically not significant (P > 0.05) between the 35th and 40th minutes of the roasting. According to the L* colour parameter as a criterion for the classification of roasted coffee colour (light, medium, dark), the Outspan sample was medium and Guaxupe sample was dark roasted.
29 December 2015 in Acta Scientiarum Polonorum Technologia Alimentaria
Coffee is one of the most widely consumed beverages in the world, because of its unique sensory properties and physiological properties. Coffee beverages represent a significant source of antioxidants in the consumers' diet and contribute significantly to their daily intake. The aim of this research was to investigate the effect of different roasting degrees on the content of biologically active compounds and antioxidant activity in different quality classes of Arabica coffee. Samples of green Arabica coffee (Rio Minas) of two quality classes from two production batches were used for the research. Roasting was carried out at temperatures of 167, 175 and 171°C. The total phenol content (TPC), total flavonoid content (TFC), flavonol content (FC) and antioxidant activity (DPPH, ABTS) in the coffee extracts was determined. This research shows that TPC was significantly higher (P < 0.05) in green coffee compared to TPC in roasted coffee, and TPC decreases as the roasting temperature increases. TFC and FC were significantly lower (P < 0.05) in green coffee than in roasted coffee. Differences in TPC between the 1st and 2nd classes of Arabica coffee were not significant (P > 0.05), while differences in TFC were significant (P < 0.05) only for green coffee from the second production batch and differences in FC were significant (P < 0.05) for green coffee and for coffee roasted at 175°C. Roasting temperatures have different influences the antioxidant activity (DPPH, ABTS) of coffee and the highest antioxidant activity was determined in coffee roasted at 171°C. An exception was 1st class Arabica coffee roasted at 167°C (ABTS). All samples of 1st class Arabica coffee had higher antioxidant activity (DPPH, ABTS) compared to 2nd class Arabica. This research shows that the bioactive compounds content and antioxidant activity of different quality classes of Arabica coffee are dependent on the degree of roasting. TPC decreases when the roasting temperature increases, while TFC and FC also increase. These results indicate that the antioxidant activity of coffee depends on a variety of bioactive components in coffee beans. Antioxidant activity largely depends on the class of coffee. The coffee samples of 1stclass quality (maximum 8 black beans/300 g from the sample and large bean size) had higher antioxidant activity compared to samples of 2nd quality class (maximum 19 black beans/300 g in the sample and medium-sized beans).
We investigated the total phenolic and flavonoid contents and the anthocyanin profiles in aqueous, ethanol and acetone extracts of Prunus spinosa (Rosaceae) fruit, and their antioxidant, antibacterial, antifungal, antidiabetic and antitumor properties. The contribution of polyphenol contents to the bioactivity of the extracts was calculated and observed through Pearson?s coefficient of correlation. The acetone extract was the richest in phenols and anthocyanins and the ethanol extract in flavonoids. Cyanidin was the most abundant anthocyanin compound in all examined extracts. The ethanol extract showed the most promising antioxidant activity in DPPH, ABTS and FRAP assays. Tested bacteria were more affected by the ethanol than by the aqueous extract. Both the ethanol and aqueous extracts exhibited potential antidiabetic effects, observed as inhibition of ?-amylase and ?-glucosidase, enzymes linked with diabetes mellitus type II. The ethanol extract was a potent ?-glucosidase-inhibitor with a significantly lower IC50 value than the positive control, glucobay, used to treat diabetes mellitus type II. Neither the ethanol nor the aqueous extracts had any effects on tested human malignant cell lines. Our results indicate that the ethanol extract showed the most pronounced in vitro antioxidant and antimicrobial effects, and a potential antidiabetic activity, which can be ascribed to its high flavonoid content. Our results indicate that research of compounds, particularly of flavonoids present in the ethanol extract and their anti-diabetic properties should be examined further.
An inadequate diet and lifestyle are major causes of various diseases. A healthy diet can prevent diseases and maintain a good health status. The present research objective was to test young consumers for their preference for healthy diets and their intention to purchase functional foods, as well as to identify factors that affect their attitudes. The study involved 720 consumers (average 20 years old), a structured questionnaire, and a specially-developed scientific methodology. The results were grouped based on sex and body mass index. The analysis focused on the points where consumers’ interest in healthy diet overlapped with health-related diet needs and how each of them corresponded with their knowledge on the following spheres: nutrition and health risks, labelled data use in food choice, preference for foods fortified with vitamins, minerals, dietary fibers, or functional foods with a poor sensory quality. The data were processed using descriptive statistics, Z-test, and correlation tests. All the consumers demonstrated healthy diet preferences and a significant positive relationship (p < 0.01) with the factors. They made an informed choice based on the labelled data and preferred foods fortified with vitamins, minerals, and dietary fibers, as well as functional products with a lower sensory quality. All respondents, regardless of sex and body mass index, demonstrated nutrition and health risk awareness. The health-related diet needs also affected their food preferences (p < 0.05), with some exceptions. The young consumers possessed sufficient basic knowledge on food quality, nutrition, and health. Their attitudes depended on their preference for healthy diets and functional foods. The novel methodology can be applied to other studies of consumer preferences.
This study was undertaken to determine the antioxidant and antimicrobial effect of essential oil and extracts of Echinophora sibthorpiana Guss. (fam. Apiaceae) collected in Macedonia. The chemical composition of E. sibthorpiana essential oil was characterized by the presence of methyl eugenol (60.40%), p-cymene (11.18%) and ?-phellandrene (10.23%). The free radical scavenging activity of extracts and essential oil was evaluated by DPPH and ABTS assays. The aqueous extract of aerial parts exhibited the strongest scavenging activity (IC50=1.67 mg/ml); results of the ABTS test showed that the most effective was the ethanol extract of aerial parts (1.11 mg vit. C/g). The essential oil showed stronger antioxidant activity compared to hydroxyanisole, ascorbic acid and quercetin that were used in the DPPH and ABTS tests, respectively. The total phenolic and flavonoid concentrations in the extracts ranged between 38.65-60.72 mg GA/g, and 3.15-19.00 mg Qu/g, respectively. The antimicrobial properties of the extracts and essential oil were investigated using a micro-well dilution technique against human pathogenic strains. The results were comparable with the effects of the positive controls, streptomycin and fluconazole. These findings indicate that E. sibthorpiana extracts and oil can be used in preventive treatments and as an alternative for synthetic preservatives.
Antioxidant and free radical scavenging activity of methanol, ethanol, ethyl acetate and chloroform extracts of aerial parts of Lamium purpureum L. was determined by DPPH, ABTS, FRAP and TRP assays. Contents of flavonoids and phenols were also investigated. The total phenolic content in the extracts, determined using Folin?Ciocalteu assay, ranged between 8.57 to 128.00 mg GAE/g d.e. while concentrations of flavonoids in the extracts varied from 24.20 to 39.80 mg QuE/g d.e. The highest phenolic content was found in methanol extract (128.00 mg GAE/g d.e.). The highest content of total flavonoids was identified in the methanol extract (39.80 mg QuE/g d.e.) and the lowest was in the chloroform (24.30 mg QuE/g d.e.). DPPH scavenging of the extracts was determined and obtained IC50 values ranged from 0.12 to 3.12 mg/mL of solution. The values of ABTS radical scavenging activity ranged from 0.35 to 1.80 mg AA/g. The highest ABTS antiradical activity was registered for methanol extract. The FRAP value was found within the range 0.08 to 1.04 ?mol Fe/mg. The best radical scavenger was methanol (1.04 ?mol Fe/mg). In reducing power assay different extracts of L. purpureum showed increasing of activity with increased concentration, and all extracts possessed substantial dose dependent antioxidant activity. The best reducing capacity was obtained with methanol extract of L. purpureum (0.0132 mg AA/mL). The results in this study confirmed that L. purpureum possesses moderate antioxidant properties.