Food Technology
Zahra Sadri Saeen; Mohammadreza Khani; Vajiheh Fadaei Noghani
Abstract
[1]Introduction: Butter is a type of dairy product made of sweet cream or sour cream. It is a perishable food that can be spoiled due to chemical changes during storage. Rancidity is one of the main problems caused by lipolysis and oxidation of fatty acids, which cause off-flavor and reduce the nutritional ...
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[1]Introduction: Butter is a type of dairy product made of sweet cream or sour cream. It is a perishable food that can be spoiled due to chemical changes during storage. Rancidity is one of the main problems caused by lipolysis and oxidation of fatty acids, which cause off-flavor and reduce the nutritional quality of butter. By adding low concentrations of antioxidant compounds, autooxidation can be prevented or delayed. It is also possible to increase the shelf life of butter by adding antioxidants. However, the carcinogenic effect of some synthetic antioxidants and consumer preference has led manufacturers to use more natural antioxidants. Chia seeds contain significant amounts of protein, fat, carbohydrates, minerals, and vitamins. Moreover, many bioactive compounds with high antioxidant potential are found in chia seeds such as phenolic acids, flavonoids, tocopherols, and sterols. Therefore, the present study was conducted to investigate the effects of chia seed extract in sweet cream butter to improve its chemical and sensory properties during refrigeration storage. Materials and Methods: For this purpose, the alcoholic extract of chia seed was prepared by adding chia seed powder to 70% ethanol (5% w/v) with stirring for 24 h, at room temperature. The filtered extracts were concentrated with a rotary evaporator. The concentrated mixture was dried in an oven at 40 °C and kept in an amber glass container in the refrigerator at 4 °C until the experiment was performed. Total phenolics content and antioxidant activity of chia seed extract were evaluated by the Folin–Ciocalteu colorimetric method using gallic acid as standard and for free radical scavenging ability by DPPH (2,2-diphenyl-1-picryl-hydrazyl) method, respectively. Then, chia seed extract was added to butter with different percentages (0.05, 0.1, 0.25, and 0.5%) and its effects on chemical properties including acidity, acid value, peroxide value, and thiobarbituric acid were evaluated for two months at 15-day intervals in refrigerated storage. Also, sensory properties including color, odor, taste, texture, and overall acceptance of butter samples were assessed using 15 untrained evaluators based on a 5-point hedonic test as above conditions. The results were reported as means± standard deviation and they were analyzed with analysis of variance using the software SPSS version 14. Statistical differences were analyzed by Duncan’s multiple range test (p<0.05). Results and Discussion: The results of total polyphenols content were 1108.78 ± 111.79 mg gallic acid per 100 g of extract and radical scavenging activity of chia seed extract in the concentration range of 4 to 20% was 35.17 ± 0.47 to 64.92 ± 2.95%. Also, the efficient concentration (EC50) of chia seed extract was 12.13 ± 0.59 mg/L in this study. It is known that the smaller the EC50, it will be the greater the antioxidant or free radical scavenging activity. According to the results, it was found that the concentration of chia extract has a significant effect on free radical scavenging (p<0.05) so that with increasing the concentration of the extract, its inhibitory properties increased. The results showed that the addition of different concentrations of chia seed extract and storage time were significant on the acidity and acid value of butter samples so that with increasing the amount of chia seed extract in treatments, the amounts of acidity and acid value increased significantly (p<0.05). Also, the acidity and acid value in all samples of butter increased significantly with increasing storage time during refrigeration (p<0.05). However, the amount of these two indices in treatments containing chia extract increased at a slower rate than the control sample during storage time, which could be due to the effect of phenolic compounds in chia seed extract in controlling the activity of lipolytic enzymes. Moreover, the results revealed that with increasing the concentration of the chia seed extract from the 15th day to the end of the storage period, the amounts of peroxide value and thiobarbituric acid of butter treatments significantly decreased compared to the control sample (p<0.05). This is due to the antioxidant effects of phenolic compounds in chia seed extract that delay the oxidation process. In this study, all chemical indices increased significantly during the storage time (p<0.05). All the samples in evaluated sensory properties were significantly different from the control sample (except odor) during 60 days of storage (p<0.05), in this way treatments had better sensory scores in color and taste properties compared to the control. In general, a concentration of 0.5% chia extract delayed oxidative damage, but in terms of sensory evaluation, a treatment containing 0.25% chia extract is selected and introduced as the most desirable treatment.
Food Biotechnology
Rana Tahmasbi; Mahta Mirzaei; Mohammadreza Khani
Abstract
Introduction: Fermented foods, probiotic, prebiotics, and symbiotic, are among the most important groups of functional food that have attracted the attention of researchers during the last years. Proteolytic activity of lactic acid bacteria can lead to the production of peptides in the fermented product. ...
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Introduction: Fermented foods, probiotic, prebiotics, and symbiotic, are among the most important groups of functional food that have attracted the attention of researchers during the last years. Proteolytic activity of lactic acid bacteria can lead to the production of peptides in the fermented product. The produced peptides can exhibit different biological activities such as antioxidant, antihypertensive, etc. that are influenced by the type of protein source, type of bacteria, time and conditions of fermentation process. Fermentation of various cereals such as quinoa seeds with high sugar and protein content by lactic acid bacteria can lead to the production of antioxidant peptides and improving their nutritional properties. Materials and Methods: In this study, the role of Lactobacillus reuteri and Lactobacillus acidophilus and the combination of two bacteria on the progress of fermentation and antioxidant activity of quinoa extract was investigated. The fermentation process was started by separate and simultaneous inoculating of Lactobacillus reuteri and Lactobacillus acidophilus and continued for 72 hours at 37° C. Sampling was performed every 24 hours of fermentation and samples were kept at -20° C for further analysis. The parameters such as pH, acidity, amount of soluble protein, degree of hydrolysis, amount of phenolic compounds and DPPH and ABTS radical scavenging activity were determined. Results and Discussion: Lactobacillus acidophilus showed higher acidification capacity than Lactobacillus reuteri. The amount of acidity in the sample fermented by Lactobacillus acidophilus increased from 0.27 to 1.13 % after 72 hours, while this amount was measured as 0.80 % for sample fermented by Lactobacillus reuteri. The amount of soluble protein and the degree of hydrolysis increased in samples fermented by both species. However, the largest increase was related to the sample fermented by Lactobacillus reuteri, so that the amount of soluble protein increased from 0.72 to 0.88 mg / ml and the value of free amino groups increased from 20.28 to 58.14 µM leucin/ mg protein during 72 hours of fermentation. The DPPH and ABTS radical scavenging activity increased in all fermented samples. The highest antioxidant activity was observed in samples fermented by Lactobacillus reuteri, followed by a combination of two bacteria (50:50) and Lactobacillus acidophilus. The amounts of phenolic compounds increased in all fermented samples. However, the highest increase was related to the sample fermented by Lactobacillus reuteri, so that it increased from 0/73 to 16.21 mg Gallic acid / ml after 72 hours of fermentation. Therefore, the results showed that despite the higher acidifying power of Lactobacillus acidophilus in quinoa extract, but Lactobacillus reuteri exhibited higher proteolytic activity, more ability to produce antioxidant peptides and also release phenolic compounds during the fermentation process.Simultaneous use of the two bacteria did not intensify the proteolytic activity and antioxidant activity of peptides, and the greatest increase in acidity, proteolysis, and antioxidant activity occurred in the first 24 hours of fermentation. Fermented extracts showed higher ABTS radical inhibitory activity than DPPH radical inhibition, indicating the hydrophilic nature of most produced antioxidant compounds. The highest levels of antioxidant activity were observed in samples fermented by Lactobacillus reuteri, a combination of Lactobacillus reuteri and Lactobacillus acidophilus (50:50) and Lactobacillus acidophilus, respectively. The results showed that fermentation by Lactobacillus reutri has the greatest effect on the production of antioxidant peptides and the release of phenolic compounds. The results of this study confirm the effectiveness of fermentation methods on improving the healing properties of quinoa extract and Lactobacillus reuteri was a more effective bacterium in fermentation and production of antioxidant peptides compared to Lactobacillus acidophilus. Simultaneous use of two bacteria did not increase the intensity of fermentation and did not improve the antioxidant activity compared to single use of each bacteria. Finally, the results of this study showed that fermentation of quinoa extract improves its antioxidant properties and has the potential to be used as a fermented beverage.
Reyhaneh Dakhteh; Mohammadreza Khani; Shahriar Dabiriyan
Abstract
Introduction: Because of the relationship between fat intake and obesity and the incidence of cardiovascular diseases, the demand for low-fat products has been increased. There are several methods to produce low fat products, which one of these methods is the use of fat replacer. The present study was ...
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Introduction: Because of the relationship between fat intake and obesity and the incidence of cardiovascular diseases, the demand for low-fat products has been increased. There are several methods to produce low fat products, which one of these methods is the use of fat replacer. The present study was aimed to partial substitution of fat in table cream by Qodume shirazi (Alyssum homolocarpum) and Persian (Amygdalus scoparia) gums. Materials & Methods: The fat content of cream was decreased from 25% (in control sample) to 18% and 15%, and each of these gums were added to the low-fat cream formulation in 0.2%, 0.3%, and 0.4% (w/w), separately to make 12 treatments. All samples were examined for physicochemical (including pH, acidity, dry matter, moisture, synersis, and viscosity) and organoleptic (including color, aroma, taste, texture and overall acceptability) properties. Results and Discussion: The results showed that the effect of type and amount of gums was significant for the pH, acidity, dry matter, moisture, syneresis, and viscosity of produced samples (P<0.05). In both types of cream (with 15 and 18 percent fat), pH of treatment containing 0.4% Qodume gum (6.81) was significantly higher than control (6.69) and other treatments (P<0.05). Moisture content of the control sample (68.7%) was lower than other treatments (73-78.7%) but dry matter of the control sample (31.3%) was higher than other treatments (21.2-26.9%) and in both creams containing 18% and 15% fat, the higher dry matter was devoted to sample containing 0.4% of Persian gum. The viscosity of cream with 18% fat containing 0.4% Qodume shirazi gum (21915 cP) and Persian gum (21919 cP) was significantly higher than the control sample (21507 cP) and other treatments. Moreover, syneresis of treatments with 18% fat containing 0.4% Qodume and Persian gums (0 ml), and also cream sample with 15% fat containing 0.4% Qodume gum (0 ml) was not observed as in the control sample (P>0.05). Evaluation of sensory properties revealed that the type of gums only had significant effect on color and the effects of cream type and amount of gums were mostly significant on texture and overall acceptance. In general, low-fat cream with 18% fat containing 0.4% Qodume and Persian gums had showed the best physicochemical and sensory results comparing to other treatments.
