Pub Date : 2023-12-18DOI: 10.17508/cjfst.2023.15.2.08
V. Oyetayo, Olabisi Omowunmi Adebisi
Probiotic drinks have become more popular and the desire for new flavours among consumers necessitates the development and production of improved probiotic drinks. In the present study, the reducing sugar, mineral content, antinutritional and antioxidant properties of non-dairy probiotic drinks produced from tigernut milk and soy milk were investigated. Probitication of the non-dairy milk results in the reduction of reducing sugars and antinutrient contents of the drinks. Probioticated tigernut milk sample (T2) has the least reducing sugar content (4.63%), while the highest was found in soy milk sample S2 (4.81%). However, there were significant increases in the mineral content and antioxidant properties of the probioticated non-dairy drinks compared to the non probioticated nondairydrinks. The ferric reducing antioxidant power (FRAP), DPPH, and Fe2+ chelation activities of probioticated tigernut milk increased from 0.5% extract to 0.84% extract, 73.18% to 91.70% and 36.30% to 39.02% in samples T12, T2 and T1, respectively. The same increase was also observed in the probioticated soy milk compared with the unprobioticated. Results from this study revealed that probiotication enhances the mineral content and antioxidative capacity of milk from soybean and tigernut.
{"title":"Chemical and antioxidant properties of two non-dairy probiotic drinks produced from tigernut (Cyperus esculentus) and soybean (Glycine max)","authors":"V. Oyetayo, Olabisi Omowunmi Adebisi","doi":"10.17508/cjfst.2023.15.2.08","DOIUrl":"https://doi.org/10.17508/cjfst.2023.15.2.08","url":null,"abstract":"Probiotic drinks have become more popular and the desire for new flavours among consumers necessitates the development and production of improved probiotic drinks. In the present study, the reducing sugar, mineral content, antinutritional and antioxidant properties of non-dairy probiotic drinks produced from tigernut milk and soy milk were investigated. Probitication of the non-dairy milk results in the reduction of reducing sugars and antinutrient contents of the drinks. Probioticated tigernut milk sample (T2) has the least reducing sugar content (4.63%), while the highest was found in soy milk sample S2 (4.81%). However, there were significant increases in the mineral content and antioxidant properties of the probioticated non-dairy drinks compared to the non probioticated nondairydrinks. The ferric reducing antioxidant power (FRAP), DPPH, and Fe2+ chelation activities of probioticated tigernut milk increased from 0.5% extract to 0.84% extract, 73.18% to 91.70% and 36.30% to 39.02% in samples T12, T2 and T1, respectively. The same increase was also observed in the probioticated soy milk compared with the unprobioticated. Results from this study revealed that probiotication enhances the mineral content and antioxidative capacity of milk from soybean and tigernut.","PeriodicalId":10771,"journal":{"name":"Croatian journal of food science and technology","volume":" 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138994622","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-18DOI: 10.17508/cjfst.2023.15.2.01
A. Yunusa, Z. B. Nouruddeen, Salisu Abubakar Adam, Muhammad Usman, Abdulrahman Mahmoud Dogara
Roasting is considered the commonest processing method applied to foods, it affects both phytochemicals and sensory attributes. In the present study, the effect of varying roasting parameters on sensory attributes was determined, as well as scavenging property against free radicals (DPPH) and polyphenolic content (TPC and TFC) of whole peanut kernels. Whole peanut kernels were roasted at different temperatures (130-150 °C) with various durations (5-20 min). Finding revealed that peanuts roasted at 130, 140, and 150 °C for 15, 10, and 5 min, respectively, received significantly the highest (p<0.05) sensory scores in all the parameters investigated. Therefore, they were selected for TPC, TFC, and DPPH assays. All three assays were found to increase during roasting compared to the unroasted counterpart. Peanuts that were roasted at 140 °C for 10 min, had the highest total phenolic contents of 67.26 ± 1.77 mg GAE/g while those roasted at 150 °C for 5 contained the highest TFC of 12.91 ± 0.56 mg QE/g. The highest DPPH radical scavenging activity was detected in the sample roasted at 140 °C for 10 min with an IC50 value of 417.44 μg/mL. Roasting significantly affected the bioactive contents as well as the scavenging activity of the whole peanut.
{"title":"Effects of roasting conditions on sensory attributes, polyphenolic content and DPPH radical scavenging activity of peanut (Arachis hypogaea)","authors":"A. Yunusa, Z. B. Nouruddeen, Salisu Abubakar Adam, Muhammad Usman, Abdulrahman Mahmoud Dogara","doi":"10.17508/cjfst.2023.15.2.01","DOIUrl":"https://doi.org/10.17508/cjfst.2023.15.2.01","url":null,"abstract":"Roasting is considered the commonest processing method applied to foods, it affects both phytochemicals and sensory attributes. In the present study, the effect of varying roasting parameters on sensory attributes was determined, as well as scavenging property against free radicals (DPPH) and polyphenolic content (TPC and TFC) of whole peanut kernels. Whole peanut kernels were roasted at different temperatures (130-150 °C) with various durations (5-20 min). Finding revealed that peanuts roasted at 130, 140, and 150 °C for 15, 10, and 5 min, respectively, received significantly the highest (p<0.05) sensory scores in all the parameters investigated. Therefore, they were selected for TPC, TFC, and DPPH assays. All three assays were found to increase during roasting compared to the unroasted counterpart. Peanuts that were roasted at 140 °C for 10 min, had the highest total phenolic contents of 67.26 ± 1.77 mg GAE/g while those roasted at 150 °C for 5 contained the highest TFC of 12.91 ± 0.56 mg QE/g. The highest DPPH radical scavenging activity was detected in the sample roasted at 140 °C for 10 min with an IC50 value of 417.44 μg/mL. Roasting significantly affected the bioactive contents as well as the scavenging activity of the whole peanut.","PeriodicalId":10771,"journal":{"name":"Croatian journal of food science and technology","volume":"429 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139173237","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-18DOI: 10.17508/cjfst.2023.15.2.02
Melita Makovec, Vesna Šimunić-Mežnarić, Valentina Vincek, D. Vincek
Varaždin pumpkin seed oil is a virgin edible oil obtained by roasting and mechanically pressing dry pumpkin seeds (Cucurbita pepo L.). The aroma is dominated by a sense of toastiness interwoven with a specific nutty taste without any foreign or rancid smell or taste. It is dark green to black in colour with a reddish glow. It is characterized by fragrant, spicy notes and a well-balanced bouquet. The basic quality chemical parameters of Varaždin pumpkin seed oil monitored over the past eight years show that the proportion of free fatty acids (expressed as oleic) is less than 1%, which indicates good quality of the raw material and the applied oil production technology. The peroxide value is less than 4 mmol O2/kg, which is an indicator of good oxidation stability of the oil during its storage. The average value of the representation of unsaturated fatty acids is more than 80%, and variations in the fatty acid composition are the result of specific climatic conditions occuring in the year of growing and harvesting pumpkins.
{"title":"Chemical indicators of the quality of Varaždin pumpkin seed oil","authors":"Melita Makovec, Vesna Šimunić-Mežnarić, Valentina Vincek, D. Vincek","doi":"10.17508/cjfst.2023.15.2.02","DOIUrl":"https://doi.org/10.17508/cjfst.2023.15.2.02","url":null,"abstract":"Varaždin pumpkin seed oil is a virgin edible oil obtained by roasting and mechanically pressing dry pumpkin seeds (Cucurbita pepo L.). The aroma is dominated by a sense of toastiness interwoven with a specific nutty taste without any foreign or rancid smell or taste. It is dark green to black in colour with a reddish glow. It is characterized by fragrant, spicy notes and a well-balanced bouquet. The basic quality chemical parameters of Varaždin pumpkin seed oil monitored over the past eight years show that the proportion of free fatty acids (expressed as oleic) is less than 1%, which indicates good quality of the raw material and the applied oil production technology. The peroxide value is less than 4 mmol O2/kg, which is an indicator of good oxidation stability of the oil during its storage. The average value of the representation of unsaturated fatty acids is more than 80%, and variations in the fatty acid composition are the result of specific climatic conditions occuring in the year of growing and harvesting pumpkins.","PeriodicalId":10771,"journal":{"name":"Croatian journal of food science and technology","volume":"18 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139173577","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
During the summer months from 2014 to 2016, water was sampled at two lakes in Zagreb, Jarun and Bundek, with the aim of determining the number of colonies of microbiological indicators of Escherichiae coli and intestinal enterococci. We have investigated the dependence of microbiological water quality indicators on sampling points. Also, we were interested in determining the influence of the season of the year. This research identified that regular monitoring of microbiological indicators is necessary, especially at locations used by people for recreation or other purposes, in order to prevent possible infections.
{"title":"Parametric statistical analysis of microbiological water quality indicators","authors":"Sanja Kovač, Anita Ptiček Siročić, Nikolina Habulan","doi":"10.17508/cjfst.2023.15.2.09","DOIUrl":"https://doi.org/10.17508/cjfst.2023.15.2.09","url":null,"abstract":"During the summer months from 2014 to 2016, water was sampled at two lakes in Zagreb, Jarun and Bundek, with the aim of determining the number of colonies of microbiological indicators of Escherichiae coli and intestinal enterococci. We have investigated the dependence of microbiological water quality indicators on sampling points. Also, we were interested in determining the influence of the season of the year. This research identified that regular monitoring of microbiological indicators is necessary, especially at locations used by people for recreation or other purposes, in order to prevent possible infections.","PeriodicalId":10771,"journal":{"name":"Croatian journal of food science and technology","volume":"27 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138964974","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-18DOI: 10.17508/cjfst.2023.15.2.05
Ž. Kurtanjek
Bayes network modelling for structural causal analysis between wine physicochemical data and quantitative human quality blind assessments is applied. The large dataset of white and red "Vinho Verde'' wine samples from Portugal, which was available from an open data repository for machine learning at the University of California at Irving, was analysed. The dataset contains 4898 white and 1599 red samples evaluated by blind tastes by a minimum of 3 sensory assessors and 12 physicochemical properties. The casual effects of wine analytic data on human quality evaluations are evaluated numerically by Bayes neural networks for adjusted sets of the covariates as marginal distributions and presented graphically as partial dependence plots. Structural causal analysis revealed important differences between the most important variables for quality predictions and the individual causal effects. Bayes neural network models of the partial dependencies show more pronounced nonlinear effects for red wines compared to white wine quality. The artificial intelligence models with boosted random decision tree forests for untrained wine samples yield a 5% relative standard error of predictions compared to 12% for the linear models and ordinary least squares estimation. For red wine, the most important direct causal quality effects are caused by alcohol, volatile acidity, and sulphates. Alcohol improves quality with a maximum plateau at 14%, while volatile acidity has a strong proportional negative effect. The effect of sulphates is highly nonlinear with maximum positive effect at a concentration of 1 g/L of K2SO4. For the white wine samples causal effects are linear with positive effects of alcohol and negative effects of volatile and fixed acidity. The developed structural causal model enables evaluation of targeted wine production interventions, named as “doing x, do(x) models”, as restructured adjusted Bayes networks. It leads to potential applications of artificial intelligence in wine production technology and process quality control.
{"title":"Wine quality analysis by the structural causal model (SCM)","authors":"Ž. Kurtanjek","doi":"10.17508/cjfst.2023.15.2.05","DOIUrl":"https://doi.org/10.17508/cjfst.2023.15.2.05","url":null,"abstract":"Bayes network modelling for structural causal analysis between wine physicochemical data and quantitative human quality blind assessments is applied. The large dataset of white and red \"Vinho Verde'' wine samples from Portugal, which was available from an open data repository for machine learning at the University of California at Irving, was analysed. The dataset contains 4898 white and 1599 red samples evaluated by blind tastes by a minimum of 3 sensory assessors and 12 physicochemical properties. The casual effects of wine analytic data on human quality evaluations are evaluated numerically by Bayes neural networks for adjusted sets of the covariates as marginal distributions and presented graphically as partial dependence plots. Structural causal analysis revealed important differences between the most important variables for quality predictions and the individual causal effects. Bayes neural network models of the partial dependencies show more pronounced nonlinear effects for red wines compared to white wine quality. The artificial intelligence models with boosted random decision tree forests for untrained wine samples yield a 5% relative standard error of predictions compared to 12% for the linear models and ordinary least squares estimation. For red wine, the most important direct causal quality effects are caused by alcohol, volatile acidity, and sulphates. Alcohol improves quality with a maximum plateau at 14%, while volatile acidity has a strong proportional negative effect. The effect of sulphates is highly nonlinear with maximum positive effect at a concentration of 1 g/L of K2SO4. For the white wine samples causal effects are linear with positive effects of alcohol and negative effects of volatile and fixed acidity. The developed structural causal model enables evaluation of targeted wine production interventions, named as “doing x, do(x) models”, as restructured adjusted Bayes networks. It leads to potential applications of artificial intelligence in wine production technology and process quality control.","PeriodicalId":10771,"journal":{"name":"Croatian journal of food science and technology","volume":"171 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139174287","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In the Zagreb city area extensive monitoring of water for human consumption has been carried out for years, which includes several dozen different chemical, biological and physical parameters. Given the daily water intake in our bodies, the possibility of ingesting certain contaminants via water has a significant role. This especially applies to nitrates, which are in the second place of importance, since it has been found that the water is their source. In this paper, we present results of the presence for the following contaminants: aluminum, cadmium, chlorate and chlorite, nitrate and mercury in water that can be consumed via water in the city of Zagreb for the period 2016-2020. The results indicate stable average annual values of monitored contaminants, except for aluminum and chlorates, for which it was found that the values of annual averages differ several times. However, even in cases of higher values, their contribution to water intake does not pose a risk to the health of consumers, nor it significantly contribute to their overall intake. Still, given the assumption that this is a specific exposure, to which the consumer is tied to the place of residence, it is important to constantly monitor trends, so that each exposure is kept to a minimum.
{"title":"Water for human consumption in Zagreb city as a possible source of some contaminants","authors":"Brigita Hengl, Jasenka Petrić, Sonja Sonja Tolić, Dragan Grubiša, Jasenka Babić, Andrea Gross Bošković","doi":"10.17508/cjfst.2023.15.2.07","DOIUrl":"https://doi.org/10.17508/cjfst.2023.15.2.07","url":null,"abstract":"In the Zagreb city area extensive monitoring of water for human consumption has been carried out for years, which includes several dozen different chemical, biological and physical parameters. Given the daily water intake in our bodies, the possibility of ingesting certain contaminants via water has a significant role. This especially applies to nitrates, which are in the second place of importance, since it has been found that the water is their source. In this paper, we present results of the presence for the following contaminants: aluminum, cadmium, chlorate and chlorite, nitrate and mercury in water that can be consumed via water in the city of Zagreb for the period 2016-2020. The results indicate stable average annual values of monitored contaminants, except for aluminum and chlorates, for which it was found that the values of annual averages differ several times. However, even in cases of higher values, their contribution to water intake does not pose a risk to the health of consumers, nor it significantly contribute to their overall intake. Still, given the assumption that this is a specific exposure, to which the consumer is tied to the place of residence, it is important to constantly monitor trends, so that each exposure is kept to a minimum.","PeriodicalId":10771,"journal":{"name":"Croatian journal of food science and technology","volume":"66 13","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139175765","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-18DOI: 10.17508/cjfst.2023.15.2.10
Stella Obianuju Dioha, R. N. Attaugwu, P. O. Uvere
This research determined the effect of red palm oil emulsification with malts of Brachystegia eurycoma, bambara groundnut and cowpea on the pro-vitamin A content of the emulsions. Bambara groundnut, B. eurycoma (“achi”) and cowpea seeds were processed by malting for 96 hours and oven dried at 50 oC before milling into flour. The malted flours were used to form emulsions with red palm oil. Pro-vitamin A contents of the emulsions were determined using standard methods and the results were as follows: B. eurycoma was in the range of 33.30 – 400.00 IU; bambara groundnut (66.67 – 333.33 IU) and cowpea (66.70 – 233.33). Emulsion stability tests indicated that the 72 and 96 hour malts gave stable emulsions after 3 hours. The emulsions obtained with the control, 72 and 96 hour malt were analyzed for anti-nutrient contents. Tannin ranged from 0.01 – 0.10 mg/100 g for achi, 0.03- 0.12 mg/100 g for bambara groundnut and 0.02 – 0.05 mg/100 g for cowpea malts, phytate was in the range of 0.03 – 1.09 mg/100 g for achi, 1.04 – 4.26 mg/100 g for bambara groundnut and 0.40 – 2.80 mg/100 g for cowpea. Malting of the achi seeds may have reduced the components that bind pro-vitamin A in the unmalted samples. Hence, malted achi is recommended for food fortification of plant based complementary foods to increase their pro-vitamin A content.
{"title":"Pro-vitamin A content of red palm oil emulsions formed with malted bambara groundnut, Brachystegia eurycoma (achi) and cowpea","authors":"Stella Obianuju Dioha, R. N. Attaugwu, P. O. Uvere","doi":"10.17508/cjfst.2023.15.2.10","DOIUrl":"https://doi.org/10.17508/cjfst.2023.15.2.10","url":null,"abstract":"This research determined the effect of red palm oil emulsification with malts of Brachystegia eurycoma, bambara groundnut and cowpea on the pro-vitamin A content of the emulsions. Bambara groundnut, B. eurycoma (“achi”) and cowpea seeds were processed by malting for 96 hours and oven dried at 50 oC before milling into flour. The malted flours were used to form emulsions with red palm oil. Pro-vitamin A contents of the emulsions were determined using standard methods and the results were as follows: B. eurycoma was in the range of 33.30 – 400.00 IU; bambara groundnut (66.67 – 333.33 IU) and cowpea (66.70 – 233.33). Emulsion stability tests indicated that the 72 and 96 hour malts gave stable emulsions after 3 hours. The emulsions obtained with the control, 72 and 96 hour malt were analyzed for anti-nutrient contents. Tannin ranged from 0.01 – 0.10 mg/100 g for achi, 0.03- 0.12 mg/100 g for bambara groundnut and 0.02 – 0.05 mg/100 g for cowpea malts, phytate was in the range of 0.03 – 1.09 mg/100 g for achi, 1.04 – 4.26 mg/100 g for bambara groundnut and 0.40 – 2.80 mg/100 g for cowpea. Malting of the achi seeds may have reduced the components that bind pro-vitamin A in the unmalted samples. Hence, malted achi is recommended for food fortification of plant based complementary foods to increase their pro-vitamin A content.","PeriodicalId":10771,"journal":{"name":"Croatian journal of food science and technology","volume":"89 s378","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138965092","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-18DOI: 10.17508/cjfst.2023.15.2.03
Marko Božinović, Tea Sokač, Anita Šalić, Ana-Marija Dukarić, M. Tišma, M. Planinić, B. Zelić
The 3,5-dinitrosalicylic acid (DNS) assay has been used for many years mainly to determine the enzymatic activity of xylanase. The assay is based on the detection of reduced sugars. Although the method is widely used, several recent studies have questioned the accuracy of the method. They mainly focused on the detection of side reactions that could lead to a false positive result of the assay. In this study, the basic components of the DNS assay such as buffer preparation, substrate source and concentration, incubation time, reagent preparation, and activity calculation were re-evaluated. Potential problems were detected and a new assay procedure was proposed. Compared to literature data, the new assay is shorter because it avoids the generation of a calibration curve and takes into account the enzyme and substrate amount when calculating enzyme activity, which is neglected in current assays.
3,5-二硝基水杨酸（DNS）测定法多年来一直主要用于测定木聚糖酶的酶活性。该测定法基于还原糖的检测。尽管该方法被广泛使用，但最近的一些研究对该方法的准确性提出了质疑。这些研究主要集中在副反应的检测上，因为副反应可能导致检测结果出现假阳性。本研究重新评估了 DNS 检测的基本组成部分，如缓冲液制备、底物来源和浓度、孵育时间、试剂制备和活性计算。发现了潜在的问题，并提出了新的检测程序。与文献数据相比，新测定法的时间更短，因为它避免了校准曲线的生成，并且在计算酶活性时考虑到了酶和底物的量，而目前的测定法忽略了这一点。
{"title":"Standardization of 3,5-dinitrosalicylic acid (DNS) assay for measuring xylanase activity","authors":"Marko Božinović, Tea Sokač, Anita Šalić, Ana-Marija Dukarić, M. Tišma, M. Planinić, B. Zelić","doi":"10.17508/cjfst.2023.15.2.03","DOIUrl":"https://doi.org/10.17508/cjfst.2023.15.2.03","url":null,"abstract":"The 3,5-dinitrosalicylic acid (DNS) assay has been used for many years mainly to determine the enzymatic activity of xylanase. The assay is based on the detection of reduced sugars. Although the method is widely used, several recent studies have questioned the accuracy of the method. They mainly focused on the detection of side reactions that could lead to a false positive result of the assay. In this study, the basic components of the DNS assay such as buffer preparation, substrate source and concentration, incubation time, reagent preparation, and activity calculation were re-evaluated. Potential problems were detected and a new assay procedure was proposed. Compared to literature data, the new assay is shorter because it avoids the generation of a calibration curve and takes into account the enzyme and substrate amount when calculating enzyme activity, which is neglected in current assays.","PeriodicalId":10771,"journal":{"name":"Croatian journal of food science and technology","volume":" 24","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138994854","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-18DOI: 10.17508/cjfst.2023.15.2.11
I. A. Okere, Olubunmi Olufemi Olusola
The potential of extract from roselle calyx on quality attributes of chicken patties marinated without extracts [plain (P1) and prepared with 0.01% butyl hydroxyl anisole; BHA (P2)] and with extract [soaked in roselle calyx extracts concentrations at 0.005% (P3), 0.01% (P4), 0.015% (P5) and 0.02% (P6)] were evaluated. Sensory qualities, cooking loss, product yield and colour [lightness (L*), redness (a*) and yellowness (b*)] were determined on freshly prepared patties and the production cost was evaluated. Total bacterial count, TBC (log10 CFU/g), water holding capacity; WHC (%), pH and lipid oxidation (mg MDA/kg) were determined on days 0, 7, 14 and 21 of cold (4 °C) storage. Patties flavour of 5.65±0.01 (P6) was higher (p<0.05) than in other treatments and the least in P1 (3.96±0.23). Cooking loss ranged from 20.24± 0.11% (P6) to 26.55± 0.01% (P1). Product yield of 79.8±0.7% (P6) was the highest, which varied significantly from other treatments. Lightness in P1 - P6 was darker than normal, with the highest L* = 42± 2.43 (P1) and the least L* = 36.44± 0.15 (P6). Redness was the least in P1 (a* = 16.85± 1.32), which varied significantly (p<0.05) from other treatments. Yellowness in P2 (b* = 54.14±1.35) was the highest, which differs significantly (p<0.05) from other treatments. Production cost varied insignificantly (p>0.05) among the treatments, with (P2 - P6) being significantly (p<0.05) higher than P1, with increasing percentage gain ranging from 0.02% (P2) to 0.78% (P6) relative to P1. On day 21, there were variations (p<0.05) in range for TBC [0.30±0.03 (P6) to 0.48±0.03 (P1)], and WHC [68.78±0.27 (P1) to 80.96±0.37 (P6)], pH [5.21±0.13 (P6) to 5.70±0.18 (P1)]. Lipid oxidation of 0.39±0.04 (P2) and 0.41±0.04 (P6) was similar, but significantly lower than 0.61±0.01 (P3), 0.59±0.04 (P4) and 0.46±0.01 (P5). Thus, among all patties marinated with extracts, those with 0.02% roselle calyx extract maintained better quality, inhibited lipid oxidation and bacteria during storage.
{"title":"Quality evaluation of chicken patties marinated with roselle (Hibiscus sabdariffa L.) calyx extract","authors":"I. A. Okere, Olubunmi Olufemi Olusola","doi":"10.17508/cjfst.2023.15.2.11","DOIUrl":"https://doi.org/10.17508/cjfst.2023.15.2.11","url":null,"abstract":"The potential of extract from roselle calyx on quality attributes of chicken patties marinated without extracts [plain (P1) and prepared with 0.01% butyl hydroxyl anisole; BHA (P2)] and with extract [soaked in roselle calyx extracts concentrations at 0.005% (P3), 0.01% (P4), 0.015% (P5) and 0.02% (P6)] were evaluated. Sensory qualities, cooking loss, product yield and colour [lightness (L*), redness (a*) and yellowness (b*)] were determined on freshly prepared patties and the production cost was evaluated. Total bacterial count, TBC (log10 CFU/g), water holding capacity; WHC (%), pH and lipid oxidation (mg MDA/kg) were determined on days 0, 7, 14 and 21 of cold (4 °C) storage. Patties flavour of 5.65±0.01 (P6) was higher (p<0.05) than in other treatments and the least in P1 (3.96±0.23). Cooking loss ranged from 20.24± 0.11% (P6) to 26.55± 0.01% (P1). Product yield of 79.8±0.7% (P6) was the highest, which varied significantly from other treatments. Lightness in P1 - P6 was darker than normal, with the highest L* = 42± 2.43 (P1) and the least L* = 36.44± 0.15 (P6). Redness was the least in P1 (a* = 16.85± 1.32), which varied significantly (p<0.05) from other treatments. Yellowness in P2 (b* = 54.14±1.35) was the highest, which differs significantly (p<0.05) from other treatments. Production cost varied insignificantly (p>0.05) among the treatments, with (P2 - P6) being significantly (p<0.05) higher than P1, with increasing percentage gain ranging from 0.02% (P2) to 0.78% (P6) relative to P1. On day 21, there were variations (p<0.05) in range for TBC [0.30±0.03 (P6) to 0.48±0.03 (P1)], and WHC [68.78±0.27 (P1) to 80.96±0.37 (P6)], pH [5.21±0.13 (P6) to 5.70±0.18 (P1)]. Lipid oxidation of 0.39±0.04 (P2) and 0.41±0.04 (P6) was similar, but significantly lower than 0.61±0.01 (P3), 0.59±0.04 (P4) and 0.46±0.01 (P5). Thus, among all patties marinated with extracts, those with 0.02% roselle calyx extract maintained better quality, inhibited lipid oxidation and bacteria during storage.","PeriodicalId":10771,"journal":{"name":"Croatian journal of food science and technology","volume":"300 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139173382","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-18DOI: 10.17508/cjfst.2023.15.2.04
Tibor Sedláček, I. Švec
The study aims to compare three methods used for the evaluation of water absorption of wheat flour: a) a direct method consisting of a standard procedure on a Farinograph-E device and b) two indirect methods, namely NIR spectroscopy and centrifugation. Forty-four samples of Czech food wheat were collected from the harvest year 2021. Namely, 23 samples of food wheat from the standard maturity collection ‘SM2’ and 21 samples from the early maturity collection ‘EM2’. All wheat samples were ground to obtain wheat flour of fine granulation. The flour samples were characterised by protein and ash content of 10.55-14.75% and of 0,59-0.63%, respectively. The water absorption ranged from 55.7% to 63.2% flour weight (Farinograph standard procedure), 60.1-67.1% flour weight (NIR spectroscopy), and 67.6-77.2% flour weight (centrifugation). Based on the results obtained by ANOVA statistical analysis, no significant difference was found for all qualitative parameters of SM2 and EM2 (p = 95%). According to the mentioned methods for both indirect determinations of water absorption in the sets SM2 and EM2, the prediction of the standard farinograph water absorption was more accurate using the NIR technique (minimal and maximal pair differences of 1.01 and 6.86 percentage points, in contrast to 1.78 and 14.87 percentage points for the centrifugation method). Linear regression confirmed the primary importance of protein content for the water absorption values. Also, the ash content should be considered because it reflects the dietary fibre level, and the fibre influences the water absorption values as well.
{"title":"Water absorption of food wheat flour – comparison of direct and indirect methods","authors":"Tibor Sedláček, I. Švec","doi":"10.17508/cjfst.2023.15.2.04","DOIUrl":"https://doi.org/10.17508/cjfst.2023.15.2.04","url":null,"abstract":"The study aims to compare three methods used for the evaluation of water absorption of wheat flour: a) a direct method consisting of a standard procedure on a Farinograph-E device and b) two indirect methods, namely NIR spectroscopy and centrifugation. Forty-four samples of Czech food wheat were collected from the harvest year 2021. Namely, 23 samples of food wheat from the standard maturity collection ‘SM2’ and 21 samples from the early maturity collection ‘EM2’. All wheat samples were ground to obtain wheat flour of fine granulation. The flour samples were characterised by protein and ash content of 10.55-14.75% and of 0,59-0.63%, respectively. The water absorption ranged from 55.7% to 63.2% flour weight (Farinograph standard procedure), 60.1-67.1% flour weight (NIR spectroscopy), and 67.6-77.2% flour weight (centrifugation). Based on the results obtained by ANOVA statistical analysis, no significant difference was found for all qualitative parameters of SM2 and EM2 (p = 95%). According to the mentioned methods for both indirect determinations of water absorption in the sets SM2 and EM2, the prediction of the standard farinograph water absorption was more accurate using the NIR technique (minimal and maximal pair differences of 1.01 and 6.86 percentage points, in contrast to 1.78 and 14.87 percentage points for the centrifugation method). Linear regression confirmed the primary importance of protein content for the water absorption values. Also, the ash content should be considered because it reflects the dietary fibre level, and the fibre influences the water absorption values as well.","PeriodicalId":10771,"journal":{"name":"Croatian journal of food science and technology","volume":"48 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139175559","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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