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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
18.10.2018.
Original scientific paper
Production of camel milk yoghurt: physicochemical and microbiological quality and consumer acceptability
The objectives of this study were to make yoghurt from camel milk and determine its physicochemical, microbiological and sensory qualities. The quality of camel milk yoghurt was compared with cow milk yoghurt and all parameters were analyzed following standard procedures. Yoghurt of acceptable consistency was made from camel milk using 1.2% gelatin, 5% bovine skim milk powder, 1.5 ml/L of calcium chloride, 40 ml/L of maple strawberry syrup and 6% yoghurt culture (YF-L811) and by incubating the milk at 42°C for 18 h. The average values for moisture, ash, syneresis, pH, titratable acidity and total solids of camel milk yoghurt were 83.4%, 1.13%, 58%, 4.37, 1.255% lactic acid and 16.7%, respectively. The corresponding values for cow milk yoghurt were 80.6%, 0.71%, 56%, 4.67, 0.865% lactic acid and 19.5%, respectively. The titratable acidity of camel milk yoghurt was significantly higher (P<0.05) than cow milk yoghurt; however, no significant difference was observed between the two yoghurt types for the other parameters. Coliforms were not detected in both yoghurt types. The sensory analysis showed that cow milk yoghurt was more preferred by the panellists than camel milk yoghurt. Production of yoghurt from camel milk using the same procedure as for cow milk yoghurt proved to be difficult. Further research is called for to improve the acceptability of camel milk yoghurt using locally available and acceptable flavouring agents. Research needs to be conducted to optimize the operating parameters and standardize the production procedures of camel milk yoghurt in the future.
Obakeng Galeboe, Eyassu Seifu, Bonno Sekwati-Monang
18.04.2018.
Original scientific paper
Optimization of osmotic dehydration of chestnut (Castanea sativa Mill.) slices using Response Surface Methodology
Osmotic dehydration of chestnut slices in sucrose was optimized for the first time by Response Surface Methodology (RSM). Experiments were planned according to a three-factor central composite design (α=1.68), studying the influence of sucrose concentration, temperature and time, on the following parameters: volume ratio, water activity, color variation, weight reduction, solids gain, water loss and normalized moisture content, as well as total moisture, ash and fat contents. The experimental data was adequately fitted into second-order polynomial models with coefficients of determination (R2 ) from 0.716 to 0.976, adjusted-R2 values from 0.460 to 0.954, and non-significant lacks of fit. The optimal osmotic dehydration process conditions for maximum water loss and minimum solids gain and color variation were determined by the “Response Optimizer” option: 83% sucrose concentration, 20 °C and 9.2 hours. Thus, the best operational conditions corresponded to high sugar concentration and low temperature, improving energy saving and decreasing the process costs.
Teresa Delgado, Bruna Paim, Jose Alberto Pereira, Susana Casal, Elsa Ramalhosa
01.12.2016.
Professional paper
Cytotoxic, antioxidant and antimicrobial properties of red sweet pepper (Capsicum annuum L. var. Llanerón) extracts: In vitro study
Rosa Raybaudi-Massilia, Alírica I. Suárez, Francisco Arvelo, Alexandra Zambrano, Felipe Sojo, María I. Calderón-Gabaldón, Jonathan Mosqueda-Melgar
01.12.2016.
Professional paper
Rheological properties of traditional balsamic vinegar: New insights and markers for objective and perceived quality
Pasquale M. Falcone, Elisa Sabatinelli, Federico Lemmetti, Paolo Giudici
01.12.2016.
Professional paper
In vitro investigation of antioxidant activities of Launea taraxacifolia and Crassocephalum rubens
Funmilayo B. Borokini, Lajide Labunmi
01.12.2016.
Professional paper
Optimization of microwave vacuum drying parameters for germinated lentils based on starch digestibility, antioxidant activity and total phenolic content
Robbarts Nongmaithem, Venkatesh Meda
01.12.2016.
Professional paper
Microbial quality and shelf life prediction of vacuum-packaged ready to eat beef rounds containing gum arabic
Johnson K. Mwove, Symon M. Mahungu, Lilian A. Gogo, Ben N. Chikamai, Mary Omwamba
18.04.2017.
Original scientific paper
Optimization of microwave vacuum drying parameters for germinated lentils based on starch digestibility, antioxidant activity and total phenolic content
The aim of this study was to optimize the processing parameters of pulse mode microwave-vacuum drying of germinated green and red lentils (CDC Greenland and CDC Maxim) and investigate the changes in their total phenolic content (TPC), total antioxidant activity (TAA) and In-vitro starch digestibility (SD). The lentils were germinated for 5 days and dried by a pulse mode microwavevacuum method, using 2 s to 8 s out of 10 s pulsed mode at 2000W microwave power and varying the vacuum pressure level between 15 and 45 kPa. In-vitro starch digestibility increased significantly with increased microwave power level. The TPC and TAA appeared to vary distinctively in the two varieties of selected lentils. Vacuum pressure levels did not significantly (p>0.05) affect any responses. Green lentils could be dried at 8 s microwave power and 45 kPa vacuum pressure and red lentils could be dried at 5.5 s microwave power and 42.19 kPa vacuum pressure. The microwave-vacuum drying showed great potential for the drying of germinated lentils.
Robbarts Nongmaithem, Venkatesh Meda
18.04.2017.
Original scientific paper
Texture analysis of blanched vegetables using high- and low-speed measuring methods
Quality reductions of raw and cooked vegetables are caused by forces generated during industrial high-speed manufacturing. However, the transferability of low-speed texture measurement methods to high speed processes is limited. Therefore, analyses with a low-speed uniaxial compression test (breaking strength σ, breaking strain ε) and a high-speed pendulum test (relative fracture height ∆h) at different speeds (3.6, 4.4, 5.3 m s−1 ) were carried out. Textural values for potatoes, carrots and celeriacs (0 to 25 min cooking time) were recorded to compare the two measurement methods. Furthermore, whether the increase of textural values of blanched vegetables measured with low-speed methods, was also observable with high-speed methods, was also investigated. Low to medium rank correlation coefficients (rS < 0.659) between parameters of the two methods were calculated. In contrast to σ and ε, ∆h-values indicate a distinct initial increase as well as textural maxima between 5.0 to 12.5 min cooking time for all tested potato and carrot varieties. On the other hand, most celeriac samples did not exhibit an increase in texture with respect to cooking time. Therefore, a textural analysis at high speeds is necessary for the prediction of textural characteristics of blanched vegetables during high-speed processing in order to reduce quality degradation.
Christian Schmitt, Thomas Friedl, Nadine Mattes, Uwe Grupa, Oliver Hensel
18.04.2017.
Original scientific paper
Vacuum-assisted microwave drying characteristics of green bell pepper
Chopped green bell pepper pieces were blanched (95 °C, 5 min) and chemically pretreated (1% potassium metabisulphite solution, 25 min at room temperature) before drying in hot air dryer (HAD) at various temperature ranges (60 – 80 °C). Three vacuum levels (200, 400, 600 mm Hg) and microwave power levels (100, 200, 300 W) were also used to dry green bell pepper samples in a vacuum-assisted microwave (VAM) (2.45 GHz, 0.8 kW) dryer. VAM drying methods offered a maximum reduction by four to five times in drying time as compared to that in HAD. The logarithmic model was found to have the best fit based on high R2 and small values of reduced χ 2 and RMSE. VAM method has higher values for effective moisture diffusivity (Deff ) and lower values for activation energy (Ea), in comparison to the HAD method.
Vivek Kumar, Shanker L. Shrivastava