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Volume 13, Issue 2, 2024
Online ISSN: 2182-1054
Volume 13 , Issue 2, (2024)
Published: 18.10.2024.
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Contents
18.10.2017.
Original scientific paper
Drying characteristics of zucchini and empirical modeling of its drying process
The aim of the study was to dry zucchini (Cucurbita pepo) by two different methods (convective hot-air (CHD) and microwave-assisted drying (MWD)). The effect of air temperature (60, 70 and 80°C), microwave (MW) power (180, 360, 540 W) and sample thickness (5 and 10 mm) on some drying characteristics of zucchini were investigated. Thirteen mathematical models available in the literature were fitted to the experimental moisture ratio data. The coefficients of the models were determined by non-linear regression analysis. It was determined that the model that fits the moisture ratio data the best varies at different drying conditions. Increasing drying temperature and MW power and reducing sample thickness improved the drying rate and drying time. Drying in microwave has reduced the drying time by 52-64% for zucchini. It was found that the effective moisture diffusivities increased with increasing temperature and MW power. MWD samples had better rehydration ratios compared to ones dried only in tray drier for 5 mm thickness.
Naciye Kutlu, Asli Isci
18.04.2017.
Original scientific paper
In vitro investigation of antioxidant activities of Launea taraxacifolia and Crassocephalum rubens
Launea taraxacifolia and Crassocephalum rubens are among many wild, underutilized and under cultivated vegetables in Nigeria that are at risk of extinction. Total flavonoid contents (TFC), total phenolic contents (TPC), and antioxidant activities of different concentrations (1-5 mg ml−1 ) were evaluated; using in vitro assays to assess the scavenging properties of 2, 2-diphenyl-1-picryl hydrazyl (DPPHRSP), nitric oxide (NORSP) and hydroxyl (OHRSP). Phenolic profiles of the alcoholic extracts were characterized using high-performance liquid chromatography techniques. The results revealed higher TFC (mg/100g RE) in aqueous (6.06±0.02-78.79±0.01) than alcohol extracts (with methanol 0.93±0.01—12.73±0.04, and with ethanol -0.85±0.01–7.70±0.03). In a similar trend, OHRSP (%) was higher in aqueous extracts (40.83±0.10–91.74±0.19) than alcoholic extracts (with methanol - 11.67±0.3–30.83±0.06; and with ethanol -14.42±0.06-40.27±0.05). TPC (mg/100g GAE) which was higher in alcoholic extracts (with methanol -21.48±0.01–133.20±0.16 and with ethanol -9.45±0.01– 59.73±0.02) than aqueous extracts (14.83±0.01–52.64±0.03) was in agreement with the trend observed for NORSP (28.24±0.05-151.76±0.08 for methanolic extracts, 21.99±0.13–49.93±0.04 for ethanolic extracts and 38.47±0.11–86.15±0.05 for aqueous extracts). DPPHRSP was also higher in alcoholic extracts (methanolic -22.81±0.01-48.41±0.05 and ethanolic–14.53±0.01-62.68±0.07) than aqueous extracts (13.66±0.13–42.86±0.03). TFC, TPC and antioxidant activities showed concentration dependent increase and strong positive correlation with TFC (r= 0.926 – 0.997and r= 0.432 – 1.000) and TPC (r= 0.825 – 0.999 and r= 0.473 - 0.994) for L. taraxacifolia and C. rubens respectively. Caffeic acid, chlorogenic acid, ellagic acid, quercetin and kaempferol were identified as major phenolic components in the extracts. The vegetables have high antioxidant potential for promoting good health; which could be attributed to the identified phytochemicals in them.
Funmilayo B. Borokini, Lajide Labunmi
18.04.2017.
Original scientific paper
Effect of inulin on dough and biscuit quality produced from different flours
One of the methods of improving the nutritional profile of baked-goods is the incorporation of dietary fibre (DF) to the formulation. However, DF retains more water than wheat flour which, affects dough rheological properties and thus the final product quality. Flour is the main ingredient in biscuits and contributes to the baked texture and shape of biscuits. There are large differences in quality among the flours from wheat cultivars and among non-wheat flours used for biscuit production. In previous works, different dietary fibres were tested and inulin was found to have a positive quality effect on biscuits made from an all-purpose wheat flour without the need of introducing significant changes in dough properties. To know whether these results are extended to different types of flours that can be used for biscuit production, this paper aimed to analyse the effects of different levels of inulin incorporation on dough and biscuits quality made from three different wheat flours and one triticale flour. Chemical and physic-chemical characterization of the flour samples was performed and compared (moisture, ashes, gluten, solvent retention capacity (SRC) and protein content). Inulin was incorporated to biscuits formulation in two levels: 6 and 12% (wheat replacement). Dough and biscuits quality was measured by spread rate during baking and biscuit factor, texture and surface colour. Inulin incorporation increased dough spreading and biscuit factor and decreased biscuit hardness. The enhancing effect of inulin was observed in all flour. The results confirmed the effect of inulin on biscuits obtained with all flour assayed, despite the differences in flour quality that was tested.
Maria S. Blanco Canalis, Alberto E. Leon, Pablo D. Ribotta
18.04.2017.
Original scientific paper
Microbial quality and shelf life prediction of vacuum-packaged ready to eat beef rounds containing gum arabic
Research has shown that gum arabic from Acacia Senegal var. kerensis can be used in beef rounds, at a level of 2.5% of the formulated product weight, as a binder and texture modifier. However, the effect of gum arabic addition on the microbial quality and shelf life of the resulting meat product has not yet been reported. Thus, the objective of this work was to study the microbial quality of beef rounds containing 2.5% gum arabic and to study shelf life based on the growth parameters of Total Viable Counts (TVC) and Lactic Acid Bacteria (LAB). Beef round samples were injected at 30% with curing brines containing gum arabic and cooked through boiling. The growth kinetics of LAB and TVC were studied for vacuum packaged sliced beef round samples stored at 7 °C and 15 °C for a period of 21 days. Baranyi and modified Gompertz models were used to fit the LAB and TVC data obtained using DMFit. Results of microbial analysis indicated that coliforms, yeasts and molds as well as pathogenic bacteria; Salmonella, Escherichia coli, and Staphylococcus aureus, were below detection limit. In addition, TVC and LAB were found to be 1.87 ± 1.09 and 1.25 ± 0.75 Log10 CFU g−1 , respectively. The results of accuracy analysis showed that both the Baranyi and modified Gompertz models were adequate in representing the bacterial growth in beef rounds injected with curing brines containing gum arabic. The predicted shelf life was found to be between 84.3 – 88.1 h and 158.0 – 173.1 h at 15 °C and 7 °C, respectively.
Johnson K. Mwove, Symon M. Mahungu, Lilian A. Gogo, Ben N. Chikamai, Mary Omwamba
18.04.2017.
Original scientific paper
A methodological approach for optimum preservation results: The packaging paradigm
The food preservation hypothesis as impacted by overall packaging applications is considered in this work. The objective was to devise a decision supportive method for the selection of “just-right” packaging materials, techniques and procedures. For that, food preservation was critically approached in order to identify the optimum outcome at experimental and packaging selection decision-making levels. A mathematically supported and proven knowledge classification, and the establishment of a straightforward coherence mode among the principles of the natural systemic phenomena, were used. The ultimate aim of this work was to justifiably surpass a simple description of packaging according to its measurable specifications, and instead, engage its inherent properties into a cyclic 8-steps-process for eventually understanding its potential to support any particular preservation hypothesis in question. The proposed methodology includes primarily, the consideration of the study hypothesis and, in parallel, the conclusive remarks and claims with respect to the experimental factors involved (properties, parameters, relations and conditions). Considering the experimentally controlled set-ups that a researcher has to expose the food system to and the role of packaging in obtaining its preservation potential, our method supports the experimenters in selecting the experimental conditions under which the preservation hypothesis can be disclaimed and furthermore, it could indicate the way to reduce experimentation research waste.
ANTONIOS KANAVOURAS, Frank A. Coutelieris
18.10.2017.
Original scientific paper
Evaluation of physical, milling and cooking properties of four new rice (Oryza sativa L.) varieties in Nigeria
This comparative study investigated some physical, milling and cooking properties of four new rice varieties (FARO 44, FARO 52, FARO 60 and FARO 61) in Nigeria. The varieties were processed into white rice and their properties analyzed separately using standard procedures. Results showed that paddy length, paddy-length-to-width-ratio, equivalent diameter, sphericity, grain volume, aspect ratio, thousand paddy grain weight, milled rice length, milled rice width, milled rice length to width ratio, milling recovery, head milled rice, broken milled rice, L*, a*, b*, elongation ratio, cooked-rice-lengthto-breadth ratio, water uptake ratio and cooking time were significantly different (p<0.05) for all the varieties. Milling recovery was found to vary from 65.3 to 68.33%; with FARO 60 having the highest head milled rice. It was observed that FARO 44 had the longest cooking time, elongation ratio and cooked rice length/breadth ratio while FARO 61 was found to have the highest water uptake ratio. There was significant positive correlation (r = 0.824) between percentage head milled rice and milling recovery while negative correlation existed between cooking time and L* (r = - 0.711). This information could be exploited by rice processors in the post-harvest processing of the varieties.
Mayowa SANUSI, Rahman Akinoso, Nahemiah Danbaba
18.10.2017.
Original scientific paper
Effect of cooking time on the physical, chemical and thermal properties of acha seeds
Acha is a less utilized cereal grain in Africa. Scaling up of the processing technology of acha seeds is desirable if accurate information on effect of processing on its properties is available. This study investigated the effect of cooking duration on the chemical and physical properties of acha seeds. Cooking times (2.5, 5, 7.5 and 10 minutes) at 100°C were used. The volume, length, breadth, thickness, porosity, density, sphericity, aspect ratio, specific heat capacity, thermal conductivity, thermal diffusivity, moisture, protein, fat, ash, crude fibre and carbohydrate were determined using standard methods. Data were analysed using ANOVA at p = 0.05. The results obtained revealed that varietal difference had a significant effect on volume, length, breadth, thickness, true density, bulk density, porosity, sphericity and aspect ratio. The moisture content, ash, protein, crude fibre, fat, carbohydrate, specific heat capacity, thermal conductivity and thermal diffusivity varied from 8.80 - 56.17 %, 0.32 - 1.87%, 1.92 - 11.50%, 0.29 - 1.58%, 0.32 - 2.81%, 40.94 - 76.26%, 1.66 -2.97 kJkg−1K −1 , 0.26 -0.43 Wm−1K −1 and 0.85 x 10−7 - 1.17 x 10−7 ms−2 respectively, as significantly influenced by cooking time. Cooking for 7.5 minutes was appropriate using the moisture uptakes and thermal properties as criteria.
Akeem O. Raji, Hajarat O. Nassam, Tawakalitu E. Aruna, Monsurat O. Raji, Maimuna Sani
18.10.2017.
Original scientific paper
Impact of selected polyphenolics on the structural properties of model lipid membranes – a review
This review is a presentation of data gathered on the interactions of several polyphenolics (i.e., phenolic acids, stilbenes, flavonoids) with lipid bilayers of different lipid compositions. These polyphenolics have been investigated through a combination of fluorescence spectroscopy, electron paramagnetic resonance spectroscopy, and differential scanning calorimetry, to detect changes in membrane fluidity. Among the investigated phenolic acids, the least polar phenolic acid, p-coumaric acid, has the greatest effect on lipid membrane structure. It appears to have a greater ability to cross membranes by passive transport than more polar phenolic acids. On the other hand, among the flavonoids that have been studied, the anthocyanins cyanidin-3-glucoside and its aglycone are inactive. All of the flavonols tested, except for epigallocatechin-3-gallate, promote small decreases in membrane fluidity. Computer simulation of electron paramagnetic resonance spectra for flavonoids indicated two or three regions in the phosphatidylcholine/ phosphatidylserine (2.4:1) membrane with different fluidity characteristics. The effects of the different flavonoids are correlated to their structural characteristics, whereby even the difference in one -OH group can be important, as can the number of H-bonds they form. The role of membrane composition and flavonoid structure in these interactions with lipid membranes are of great importance for bioavailability of these compounds and for their biological effects in an organism.
Natasa Poklar Ulrih, Ajda Ota, Veronika Abram
18.10.2017.
Original scientific paper
Food science and technology students self-evaluate soft and technical skills
Food Scientists and Technologists (FS&T) need diverse skills in the globalized food and drink sector: Food-specific or scientific / technical skills and generic or intuitive soft skills. This study determined how satisfied FS&T students were with overall improvement, and in key technical and soft skills, based on their university work; and if satisfaction was linked to geography, degree in progress, anticipated degree, anticipated work place or anticipated job responsibility. An on-line survey was completed by 267 students in over 20 countries using a 5-point Likert scale to evaluate satisfaction. Responses were analyzed by the Friedman or Kruskal Wallis tests for more than two groups, otherwise by the Wilcoxon Signed Rank or Mann-Whitney tests. There were no differences in Overall Satisfaction with technical and soft skills training. Among soft skills, training in Working with Others and Being Responsible were more often rated “Excellent” and students were more satisfied with their training than with Solving Problems, Communication and Positive Attitude. Students anticipating a job with high responsibility were more satisfied with overall soft skill training and with 3 of the 5 specific soft skills. Among technical skills, students were more satisfied with improvement in basic sciences (Microbiology, Chemistry, Processing, Safety), and those in Northern Europe were more satisfied with overall technical training. These data show variations in perception and/or efficacy of technical and soft skill training in Food Science programmes and underline the need for separate attention to the incorporation of soft skill training into the design of FS&T courses.
Katherine M. Flynn, Peter Ho, Margarida C. Vieira, Paola Pittia, Marco Dalla Rosa
01.12.2016.
Professional paper
Effect of inulin on dough and biscuit quality produced from different flours
Maria S. Blanco Canalis, Alberto E. León, Pablo D. Ribotta