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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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18.01.2020.

Original scientific paper

A numerical model for studying the thermal denaturation-aggregation of whey proteins under continuous thermal processing

A computational fluid dynamics model was designed to study the problem of thermal processing of a liquid food product containing whey proteins within a heat exchanger consisting of heating, holding and cooling tubular sections. This physical problem is associated with strong coupling between the phenomena of fluid flow, heat transfer, and thermal denaturation-aggregation of whey proteins. Our primary objective was to investigate the two-way coupling between these phenomena within the heat exchanger. This was carried out by analyzing the model predictions of velocity, temperature and product properties at both axial and radial directions. Attention was focussed on the whey proteins present in a cream cheese formulation. The thermal denaturation-aggregation kinetics was supposed to follow that of the beta-lacto-globulin, which plays a major role in fouling when milk derivatives are submitted to thermal processing in heat exchangers. Model predictions demonstrated that the apparent viscosity of the liquid product exhibited a complex behavior along the processing unit: in addition to its dependence on local temperature, it was affected by the local degree of denaturation of whey proteins – and hence on the product history previous to this position in the heat exchanger. The numerical model was structured into a sequence of computational domains; its versatility was illustrated by changing the length of the holding section and then assessing the impact on the final degree of denaturation of the whey proteins present in the liquid product.

Artemio Plana-Fattori, Christophe Doursat, Alienor Coutouly, Alain Riaublanc, Denis Flick

18.10.2020.

Original scientific paper

Quality of postharvest strawberries: comparative effect of fungal chitosan gel, nanoparticles and gel enriched with edible nanoparticles coatings

This study compared, for the first time, the postharvest conservative action of edible fungal chitosan coatings (gel, nanoparticles and gel-nanoparticle) on the physico-chemical, sensorial and microbiological characteristics of strawberries. The nanoparticles were prepared by an ionic gelation method and characterized by dynamic light scattering and scanning electron microscopy. The antioxidant (DPPH* and ABTS*) activity of the edible coatings and the antimicrobial (macrodilution method) action against phytopathogenic fungi were verified. The nanoparticles had a size of 331.1 nm and a zeta potential of+ 34 mV. The gel, nanoparticles and gel+nanoparticles exhibited minimum inhibitory concentration values ranging from 4 to 5, 1.5 to 2.5 and 1.0 + 0.5 to 2.0 + 1.5 g.L-1, respectively. All the edible coatings exhibited antifungal action. All the coatings had high scavenging activity, especially the gel edible coating. The coatings, especially the gel+nanoparticles, decreased the weight loss, microbiological growth, soluble solids, maturity index and moisture loss of the strawberry and preserved the pH values, anthocyanin content, titratable acidity and sensory characteristics. Therefore, the use of chitosan edible coating containing nanoparticles can be a promising strategy to improve the post-harvest quality of strawberries.

Natália Melo, Maria Manuela Estevez Pintado, José Alberto da Costa Medeiros, André Galembeck, Margarida Angélica da Silva Vasconcelos, Viviane Lansky Xavier, Marcos Antônio Barbosa de Lima, Tânia Lucia Montenegro Stamford, Thatiana Montenegro Stamford–Arnaud, Miguel Angel Pelágio Flores, Thayza Christina Montenegro Stamford

18.10.2020.

Original scientific paper

Estimation of the dietary exposure of polycyclic aromatic hydrocarbons in Syria and their health risks assessment

In this work, the exposure of people, through their diet, to polycyclic aromatic hydrocarbons (PAHs) has been assessed for the urban, rural, and general populations in Syria. The food categories consumed have been divided into major groups, and the health risk assessment on dietary exposure of PAHs determined in each food category. For this purpose, two approaches were used: incremental lifetime cancer risk (ILCR) and margin of exposure approach (MOE). The results showed that each of the following food categories: oils and fats, meat and meat products, vegetables, and cereals dominantly contribute in the dietary exposure of PAHs. Also their MOE values are the lowest. Additionally, they have higher ILCR values. Therefore, these groups are a main risk source to health. On the other hand, the dietary exposure of PAHs in each of urban, rural and general populations was of low health concern, whereas their ILCR values reached to 10E-05 in total food categories, nevertheless it remains lower than serious risk level (ILCR>10E-04). This work is the first study that is dealing with dietary exposure of PAHs and their health risk assessment in Syria.

Hour KRAJIAN

18.10.2020.

Original scientific paper

Physicochemical and sensory characteristics of green coconut (Cocos nucifera L.) water kefir

This research aims to examine the effects of fermentation time on the physicochemical and sensory characteristics of green coconut water kefir in order to determine the optimal fermentation time based on the resulting sensory attributes. There were four fermentation time treatments (12, 24, 36, and 48 hours), each with five replications. The materials used were green coconut water and 5% kefir grains. Physical analyses included pH and viscosity, while the chemical analyses included total dissolved solids (TDS), alcohol content, water content, protein content and fat content. Sensory attributes included sourness, soda sensation, sour aroma, viscosity and turbidity. The results showed that fermentation time had significant effects on pH, TDS, alcohol content, water content, protein content and the sensory attributes of green coconut water kefir. Viscosity and fat content were not affected by fermentation time. The ideal fermentation time was 12 hours resulting in a pH level of 4.6, viscosity of 0.09, TDS of 3.8° Brix, alcohol content of 1.16%, water content of 97.14 %, protein content of 6.64 % and fat content of 1.17%. Sensory evaluation found a low level of sourness, low soda sensation, high sour aroma, high viscosity and low turbidity.

Bambang Dwiloka, Heni Rizqiati, Bhakti Etza Setiani

18.10.2020.

Original scientific paper

Assessment and Evaluation of Student Learning Through a Project-Based Assignment on Note by Note Cooking

Many innovative teaching and learning methods are used in higher level education including project-based learning (PBL). Since 2012 a PBL assignment project has been undertaken by master students of the Advanced Molecular Gastronomy module at Technological University Dublin (TU Dublin). The aim is to stimulate student learning and creativity by using Note by Note cooking in a PBL assignment while at the same time complying with the requirements of the annual International Note by Note contest which is held in Paris, France. Direct and indirect assessment methods were used to assign individual grades and to gather student feedback about the module. The direct methods were both formative and summative. The indirect method used was a student feedback questionnaire. Results to date (2012-2019) showed that 92% of learners successfully passed the module. However, further evaluation of individual assessment results revealed that most students achieved higher scores for finding and using resources, asking further questions and developing their own answers than for analysing, synthesising and evaluating information (P≤0.01). Overall students were happy with the module content and said that they learnt about Note by Note cooking, chemical compounds, researching, independent-thinking and perseverance. In future students should carry out a more in-depth analysis, synthesis and evaluation of information.

Róisín M. Burke, Pauline Danaher

18.01.2020.

Original scientific paper

Improvement of microbiological quality of hen egg powder using gamma irradiation

Eggs and their products such as desserts, confectioneries, bakery mixes, mayonnaise and many convenience foods have been implicated in food-borne disease outbreaks due to microorganism contamination. The effect of gamma irradiation on the presence of microorganisms in egg powder was investigated. Egg powder samples were exposed to several doses of irradiation: 0, 5, 10 and 15 kGy and stored for up to 12 months at ambient temperature (25 oC). Results indicated that the total viable count (TVC) (5.56 log10 cfu g-1), total coliform counts (TCC) (6.46 log10 cfu g-1) and mold and yeast counts (MYC) (9.12 log10 cfu g) in un-irradiated (control) samples of egg powder were higher than the maximum limits (4.88, 2.00 and 1.70 log10 cfu g-1, respectively). Application of the higher doses (10 and 15 kGy) decreased the TVC, TCC and MYC of the egg powder samples to less than 1 log10 cfu g-1 and the counts remained almost constant during storage for 12 months. D10 values for Escherichia coli and Salmonella typhimurium were 0.714 and 0.278 kGy, respectively. Gamma irradiation treatment could be chosen on the basis of preliminary microbiological tests including TVC, TCC and MYC and help improve the hygienic quality by killing and reducing the microorganisms that might be present inside of egg powder to meet national and international standards.

M. Al-Bachir

18.01.2020.

Original scientific paper

Textural, rheological and sensory properties of spreadable processed goat cheese

The aim of this work was to study the influence of the ripening degree of natural goat cheese on texture, rheological and sensory properties of processed cheese products. Processed cheeses were formulated using goat cheeses with 10, 20, and 40 days of ripening. We obtained four different formulations by varying the proportions of these cheeses in each formulation. The variation in major α, β, and para-κ casein fractions, rheological properties, and the texture of samples were determined, and a sensorial evaluation was carried out. Cheeses from Formulation 2 (50% cheese ripened for 10 days, 25% cheese ripened for 20 days and 25% cheese ripened for 40 days) had greater values of α and β –caseins, which is related to a greater content of intact casein resulting from a cheese with short ripening time. Hardness, adhesiveness and complex modulus (G*) decreased as the degree of ripening of the natural cheese (raw material) increased. Formulation 2 presented a G* value similar to that of the commercial processed cow cheese and the greatest firmness. Formulation 2 presented the characteristics we aimed to obtain, described as spreadable, slightly acid and salty cheese.

Laura Burgos, Nora Pece, Silvina Maldonado

18.10.2020.

Original scientific paper

Research, development and capacity building for food and nutrition security in sub-Saharan Africa

This paper focuses on research, development, and capacity building in relation to food and nutrition security (FNS) in sub-Saharan Africa (SSA). It looks at human capacity, education, teaching and learning, women empowerment, research, innovation and technology, research, indigenous knowledge (IK), institutional aspects, infrastructure, information and communication technologies (ICT), policies and finance. Professional bodies exist in many countries and the extent to which they engage in FNS awareness creation differs. Food and nutrition insecurity continues to affect people in Africa’s 54 nations where the population is expected to double by 2050 with the expected doubling of food production to keep pace with population growth. Within the continent there is a substantial number of human capacity professionals who are global leaders in food, nutrition and related professions. Some research organisations in the continent directly or indirectly benefit from grants administered by developed economies but a challenge exists with brain drain and ageing of qualified and experienced experts. Increasing educational need, coupled with the growing population necessitates attention to ensuring a sustained supply of highly trained, adequately equipped and qualified professionals in the relevant fields of food and nutrition sciences. Higher educational institutions exist in especially those that fall within the 500 in world universities ranking. Research activities take place in the continent along with the translation of research outputs into commercialisable products. Research towards transforming agriculture for improved livelihoods is taking place in different parts of the continent. Education, governance, gender and rural development are the key challenges. Income growth and the impacts of climate change on food production have contributed to food insecurity. ICTs can play an important role for FNS. Strengthening research, development, capacity building and industry cooperation are critical for FNS in Africa.

Afam I. O. Jideani

18.10.2020.

Original scientific paper

Cooking and functional properties of parboiled milled local rice marketed in the south-east zone of Nigeria

Imported rice is perceived to have better cooking properties than locally grown rice in Nigeria and it has increased its market share while reducing patronage for local rice. Rice in Nigeria has many applications, including consumption as whole cooked grain or dumpling or use as an adjunct in making beverages. Eighteen varieties of parboiled milled local rice and three imported rice varieties, coded Ip1, Ip2 and Ip3, were studied for their cooking and functional properties using standard methods. There was a significant (p<0.05) increase in the dimensions of all the rice varieties when cooked. There was a 25 g increase in the grain weight and an elongation ratio of more than 1.26 in all the rice varieties. Ghesua had the highest cooked grain weight (68.67 g) while Omor-Mas (6.00) and R-Bus (6.00) had the highest volume expansion ratio (VER). The VER was more than 3.00 for all the rice varieties. All the local rice varieties imbibed less water (17.67-25.33 ml) compared to the imported rice varieties (26.00-27.67ml) before they reached their optimum cooking time. The imported rice varieties were of soft gel consistency (89.67-73.50 mm) and intermediate amylose content (20.71-23.14 %) while the local rice varied in amylose and gel consistency. Abakiliki-Mas (27.00 mm) and R-8 (33.67 mm) were of hard gel-consistency, intermediate (21.11 %) and high amylose (27.21 %) content respectively and have not been exploited although they would be appropriate for making canned rice, dry mixes and rice-noodles.

Chinenye Azuka, Iro Nkama, Chinwendu R. Eze, Nahemiah Danbaba, Felix U. Asoiro

18.01.2020.

Original scientific paper

Evaluation of gum arabic from Acacia senegal var kerensis and Acacia senegal var senegal as a stabilizer in low-fat yoghurt

Gum arabic is a dried, gummy exudate obtained from the stems and branches of Acacia senegal and Acacia seyal. In Kenya, gum arabic comes from Acacia senegal var kerensis although its exploitation for commercial and industrial application is marginal. Therefore, the aim of this study was to characterize and determine the effect of the gum from A. senegal var kerensis on the quality characteristics of set low-fat yoghurt compared to gum arabic from A. senegal var senegal, with a view to increasing its utilization locally. Yoghurt was prepared containing gum arabic at four concentrations (0.2%, 0.4%, 0.6%, 0.8% gum w/v).  Results showed that A. senegal var kerensis gum had higher molecular weight and gelling properties compared to A. senegal var senegal gum. In addition, A. senegal var kerensis gum was less susceptible to syneresis and showed a higher absolute viscosity compared to A. senegal var senegal gum at all concentration levels. Sensory evaluation revealed that addition of gum arabic significantly improved the body and the texture of the yoghurt. Therefore, A. senegal var kerensis gum is a better yoghurt stabilizer than gum arabic from A. senegal var senegal. An optimal gum concentration of 0.6% of A. senegal var kerensis gum in low-fat yoghurt is recommended from the results of this study.

Edward Muita Mugo, Symon M. Mahungu, Ben N. Chikamai, Johnson Mwove

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