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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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18.10.2015.

Original scientific paper

Teaching microbiological food safety through case studies

Higher education students usually ask for more training based on case studies. This was addressed by designing a specific food safety module (24 hours) in which students were shown how to predict microbiological risks in food products i.e. they were asked to determine product shelf-life according to product formulation, preservation methods and consumption habits using predictive microbiology tools. Working groups of four students first identified the main microbiological hazards associated with a specific product. To perform this task, they were given several documents including guides for good hygiene practices, reviews on microbiological hazards in the food sector, flow sheets, etc. . . After three-hours of work, the working groups prepared and gave an oral presentation in front of their classmates and professors. This raised comments and discussion that allowed students to adjust their conclusions before beginning the next step of their work. This second step consisted in the evaluation of the safety risk associated with the two major microbiological hazards of the product studied, using predictive microbiology. Students then attended a general lecture on the different tools of predictive microbiology and tutorials (6 hours) that made them familiar with the modelling of bacterial growth or inactivation. They applied these tools (9 hours) to predict the shelf-life of the studied product according to various scenarios of preservation (refrigeration, water activity, concentration of salt or acid, modified atmosphere, etc. . . ) and/or consumption procedures (cooking). The module was concluded by oral presentations of each working group and included student evaluation (3 hours).

Florence Dubois-Brissonnet, Laurent Guillier, Murielle Naıtali

18.10.2015.

Original scientific paper

Information literacy training in AgroParisTech food studies

AgroParisTech professors and librarians in Food Science and Technology have developed information literacy instruction to help students find and use relevant information. The course trains students to develop information literacy competencies: to identify the information needed and define its nature and extent; to access the information with efficiency because they select and use methods, resources and retrieval systems most appropriate to the topic; to evaluate the used methods, information, and sources; to search, access and use information ethically and legally; to read, use and write bibliographic references.
AgroParisTech trains two kinds of students. For Higher Education students (engineering students), the training takes place at their arrival in AgroParisTech, including courses and practical classes: role and management of information in organizations; information on plagiarism; resources in environment, food science and technology; use of relevant tools and methods for searching in databases; reference writing.
For students attending a Master of Science, the training prepares them to produce a literature review. The curriculum includes: information about scientific integrity, plagiarism; information needed for a researcher; critical reading of a journal article; how to manage a literature review: resources used, information search with databases, full text access; reference writing. The students will use these information literacy skills along their studies as well as in their future jobs.

Agnès Grimal, Florence Dubois-Brissonnet, Elisabeth Dumoulin

18.04.2015.

Original scientific paper

Mechanical properties of cassava starch films as affected by different plasticizers and different relative humidity conditions

The influence of plasticizer type (glycerol and sorbitol), its content (starch:plasticizer ratio of 1:0.15; 1:0.20; 1:0.25 and 1:0.30) and the relative humidity conditions (43, 58, 75 and 85%) on the mechanical properties of cassava starch films was studied. Both plasticizers seemed to integrate homogeneously in the film matrix. The incorporation of different concentrations of plasticizers affected the mechanical properties of the cassava starch films. Plasticizer ratio directly influenced the force values of the films, they showed significant flexibility when the plasticizer proportion was increased in the formulation. Under conditions of low relative humidity, sorbitol produced films more resistant to puncture than glycerol. Qualitatively, all the films were less brittle when the plasticizers were incorporated.

Jeannine Bonilla Lagos, Nıvea M. Vicentini, Rodolfo M.C. Dos Santos, Ana Monica Q.B. Bittante, Paulo J.A. Sobral

18.10.2015.

Original scientific paper

Identifying most important skills for PhD students in Food Science and Technology: a comparison between industry and academic stakeholders

Nowadays, there is an increasing need of new skills for PhD students to face the future labour market prospects. PhD graduates must have qualities attractive not only in academia but also outside, in both manufacture and service-oriented enterprises, in small innovative companies, and in the civil services and public administration, among others. To know what the needs of these future employees are, is of great importance to be able to improve their personal and academic formation. The aim of this work was, in the framework of the EC-funded ISEKI Food 4 network, to evaluate the most desirable specific and soft skills that PhD students should acquire by the end of their doctoral studies. To this aim,
several surveys were conducted and sent to the different stakeholders (academia and food industry partners) in order to collect the information needed. Results showed that competences related to research skills and techniques, research management, personal effectiveness and communication skills were considered to be the most valuable skills to be acquired by our PhD students to meet the future needs of the labour market. The importance of these skills was appreciated differently, depending on the stakeholder. To sum up, some recommendations to integrate such valuable skills into the curricula of the PhD student are given.

Chelo Gonzalez-Martınez, Peter Ho, Luis Cunha, Oliver Schluter, Paola Pittia

18.04.2015.

Original scientific paper

Almond milk fermented with different potentially probiotic bacteria improves iron uptake by intestinal epithelial (Caco-2) cells

New fermented almond milks were developed, using different potentially probiotic bacteria, in order to meet the current demand for healthy, versatile non-dairy products. An in vitro digestion/Caco2 cell model was used to evaluate the effect of both non-fermented and fermented almond milks on the mitochondrial enzymatic activities of enterocytes. Moreover, macrophages were challenged with the in-vitro digested samples and the production of pro-inflammatory biomarkers TNF-α and IL-6 was quantified. Enzymatic activities of cell cultures seemed to be stimulated by the exposure to both fermented and non-fermented almond milks. Both biomarkers decreased (p< 0.05) in fermented almond milks with either B. bifidum or B. longum. Results showed that fermented almond products favored the energetic metabolism of enterocytes and had a lower inflammatory response than non-fermented almond milk, suggesting its benefits for the management of allergies/intolerances. Moreover, the fermentation process enhanced the uptake of iron by Caco-2 cells, especially when using L. rhamnosus and either B. bifidum or B. longum as starters, thus improving the product bioactivity. Therefore, new nondairy fermented products with functional properties were developed, which might be positioned as alternatives to cow-milk products for sensitized groups of population (allergic and/or intolerant to cow milk or anemic population, among others).

Neus Bernat, Maite Chafer, Amparo Chiralt, Jose Moises Laparra, Chelo Gonzalez-Martıne

01.12.2014.

Professional paper

Applicability of Mixolab test with local wheat flours

Several types of equipment have been used to predict dough behaviour during breadmaking. The complexity of requirements means that no device is able to predict all the properties, and therefore, new tests are released continuously. The Chopin Mixolab mixes the dough at different temperatures, allowing the study of dough mixing properties, weakening, gelatinization, gel stability and retrogradation in one test. The objective of this work was to study the suitability of the Mixolab to predict rheological properties and breadmaking quality of local wheats. Flour was obtained from 29 wheat samples  from different genotypes and environments. The correlation of results from traditional analyses  (test weight, protein content, sedimentation volume, wet gluten, Falling Number, Alveograph and Farinograph)  with Mixolab parameters was studied. The properties of two different bread types were compared with all these parameters. Stability and water absorption values from the Farinograph were highly correlated with the respective Mixolab parameters. It was concluded that wheat samples could be sorted by mixing properties in similar order independently of which method was used. Beyond that, gluten strength estimators obtained from these three rheological methods and the sedimentation volume test were highly correlated. Whilst the correlation of Mixolab parameters with pan loaf volume was not as high as traditional ones, Mixolab developing time, stability and C5 were the best correlated with the most important hearth bread characteristics. Studies performed by other researchers, using wheats from diverse origins, found different results. The need for empirical rheology evaluation with local wheat samples was proved.

Daniel Vazquez, María C. Veira

18.10.2014.

Original scientific paper

Effect of pre-treatments on solar drying kinetics of red seedless grapes (cv. Monukka)

Two different pre-treatments were applied to grapes prior to drying in a mixed mode solar dryer. Grapes were blanched in water and in a 0.1% sunflower oil water emulsion, both at 99◦C and for approximately 15 seconds. Several models were tested to fit the experimental data of drying curves but the normalized Newton model gave the best fit results. Samples blanched in hot water or in the 0.1% edible oil emulsion had faster drying rates than untreated samples. Contrary to what was expected, pre-treating with the 0.1% edible oil emulsion did not increase the drying rate to a higher extent than blanching. Pre-treatments did not give a noteworthy difference in the total drying time. However, they had an important role in accelerating initial drying rates, thus preventing moulds and bacterial growth and consequently increasing farmers’ income

Ines N. Ramos, Teresa R.S. Brandao, Cristina L.M. Silva

18.04.2014.

Original scientific paper

Dried Fruit Matrices Incorporated with a Probiotic Strain of Lactobacillus plantarum

The development of fruits and vegetables containing probiotics is a topic of great interest and popularity for health-conscious consumers. The aim of this study was to evaluate the possibility of using dried fruit matrices as delivery vehicles for probiotics. Different fruits — kiwi, mango, strawberry, pineapple, banana — were used as food matrices to test the viability of a strain of Lactobacillus plantarum, which was determined after drying at 40ºC and at different storage times. Cell survival after drying decreased by ca. 1 log in banana and strawberry, to 3 log, for kiwi. The bacterial numbers in banana and strawberry dried pieces at the time of storage at room temperature and 4ºC were approximately 107 cfu/g. After 37 days storage at room temperature, no viable counts were observed in any of the fruits studied. However, at 4ºC after this period of time, viable cells were detected for all the fruits (1.9x106 cfu/g, 1.5x105 cfu/g 1.5x105 cfu/g, 4.7x104 cfu/g 8.0x103 cfu/g, for strawberry, banana, kiwi, mango and pineapple, respectively).

Catarina Ribeiro, Ricardo Freixo, Joana Silva, Paul Gibbs, Alcina Morais, Paula Teixeira

18.04.2014.

Original scientific paper

Effect of texturized soy protein on quality characteristics of beef samosas

Texturized soy protein (TSP) granules obtained from defatted soy flour were used to replace beef at 25, 50, 75 and 100% levels in samosa stuffing. The moisture, protein and ash content of the stuffing increased with an increase in the amount of texturized soy protein while the fat content decreased significantly (p<0.05) with an increase in the amount of texturized soy protein. Sensory evaluation of baked samosas showed no significant (p>0.05) difference in appearance, taste and overall acceptability with inclusion of texturized soy protein. However there were significant (p<0.05) differences in flavour, texture and willingness to purchase between 100% beef and 100% TSP samosas. There was a reduction in the moisture content while the protein, fat, ash and carbohydrate content increased in baked as compared to raw samples, both in the control and TSP50 samosas. The caloric value of the baked samosas was 24.07% lower in TSP added samples compared to 100% beef samples (control). Lipid oxidation increased with storage time from 0.25 to 0.68 mg malonaldehyde/kg in the control and from 0.21 to 0.39 mg malonaldehyde/kg in TSP50 samosas. The oxidation in the control was significantly (p<0.05) higher than in TSP50. The results suggest that TSP granules can be use with up to 50% addition in samosa products without significant differences in sensory attributes.

Mary Omwamba, Symon M. Mahungu, Abdul K. Faraj

18.10.2014.

Original scientific paper

Stability of cupuaçu (Theobroma grandiflorum) nectar during storage

A shelf-life study on cupua¸cu nectar (Theobroma grandiflorum) was carried out in two parts. Part I studied the microbial stability of the regular nectar (batch R) and the same nectar fortified with synthetic ascorbic acid (AA) (batch F), pasteurized at 90 ◦C for 3 min and hot filled in glass bottles. Total Plate Count (TPC), yeast and molds as well as pH, total soluble solids (TSS), titratable acidity and hidroxymethylfurfural (HMF) were followed along 43 storage days at 4, 25 and 35 ◦C. At the end of the storage period neither TPC nor molds or yeast had recovered the initial loads observed before pasteurization, for both R and F batches. Right after pasteurization, acidity increased slightly, pH decreased from 3.52 to 3.3, and TSS increased from 18.7 to 19.0 ◦Brix, with all stabilizing afterwards. Part II evaluated ascorbic (AA) and dehydroascorbic (DHAA) acids’ stabilization in the two batches, R and F, and dissolved oxygen (DO) was monitored. Both batches were stored at the same temperatures as in Part I for two months. For batch R, the AA degradation results followed a reversible first order reaction (EaAA(R) =-34±6 kJ/mol, k AA(R)25◦C =0.006±0.003 days−1 , C0AA(R)=0.92±0.01 and C ∞AA(R)= 0.43±0.19). For the (F) nectar, the experimental data fitted a first order model well (EaAA(F )=30±17 kJ/mol, k AA(F )25◦C =0.0016±0.0004 days−1 ). DO was modeled as a fractional conversion model (EaDO= 67±17 kJ/mol, kDO25◦C = 1.94±0.94 days−1 , C0DO=0.97±0.03 and C ∞DO= 0.55±0.01). For both nectars, storage at environmental temperatures was preferred (AA retention above 80%) to refrigeration, due to the slower rate of diffusion of DO at lower temperatures. 

Margarida Vieira, Cristina L. M. Silva

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