Contents
01.12.2014.
Professional paper
Simple and double microencapsulation of Lactobacillus acidophilus with chitosan using spray drying
The aim of this study was to evaluate the survival of Lactobacillus acidophilus that had been simple or double spray dried using chitosan to cause microencapsulation and which had been exposed to model gastrointestinal conditions. In addition, the study also determined the physicochemical properties of the powder containing the microencapsulated probiotic.Chitosan-inulin or chitosan-maltodextrin (1:15 or 1:25) solutions were inoculated with 1012 cfu mL-1 of L. acidophilus, for simple microencapsulation. The different solutions were dried using a spray dryer with an inlet air temperature of 130°C and a solution flux of 4.8 g min-1. A two-step process was used for the double microencapsulation. In the first step, the probiotic was added to a gelatin-maltodextrin (1:25) solution and then spray dried; for the second step, the microencapsulated probiotic was added to a chitosan-inulin or chitosan-maltodextrin (1:25) solution and then it was spray dried again.With the simple microencapsulated probiotic, a microbial reduction of 7 log cycles was obtained. With the double microencapsulated probiotic only 3 log reductions were achieved. The double microencapsulated probiotic thus demonstrated greater resistance to simulated gastrointestinal conditions. The powders produced were shown to have water activity values of 0.176 - 0.261 at 25 °C and moisture content of 0.8 – 1.0%, which are characteristic of spray dried products. The bulk density was significantly (p < 0.05) lower (300 kg m-3) for simple than for double (400 kg m-3) microencapsulated probiotic powders. Solubility and dispersibility of the powder microcapsules were better at lower pH values.Double microencapsulation using a process of spray drying is therefore recommended for probiotics, thus exploiting chitosan’s insolubility in water, which can be applied for the of development food products.
Isela A. Flores-Belmont, Enrique Palou, Aurelio López-Malo, María Teresa Jiménez-Munguía
01.12.2014.
Professional paper
Food innovation and entrepreneurship in higher education: a case study
Food innovation and entrepreneurship are important topics in graduate food studies. Students should be challenged to promote an innovative attitude towards their future career in the food industry sector, as professionals working in a small and medium-sized enterprise, or in a large multinational company, or even as entrepreneurs with their own working projects. The present case study shows a curricular unit of a master course that intends to integrate the knowledge on new and sustainable technologies and products, based on seminars of experts on hot topics, on visits to food industry enterprises and market expositions and on the development of a state-of-the-art report about an emergent or novel food technology or product with oral presentation. Hot topic seminars included edible coatings, bioprocessing, allying tradition and innovation in food products, new convenience foods, challenging tests, and new clean and sustainable processes. Entrepreneur alumni lectures were also promoted allowing exchange of experiences. Visits included a high pressure technology unit of a food industry, an innovation and development department of a food industry, an entrepreneurship centre and a food exhibition. A satisfaction survey was made, through the response of a questionnaire by the students, proving the effectiveness and success of this unit course framework. A SWOT analysis was carried out to gain a better understanding of the strengths, weaknesses, opportunities, and threats involved in the curricular unit objectives.
Susana C. Fonseca, Rita Pinheiro, Carla Barbosa, Alberta Araújo, Manuela Vaz-Velho, Rui Alves
01.12.2014.
Professional paper
Effect of incorporating alum in cane juice clarification efficiency and sucrose losses
The effect of incorporating alum in the clarification stage of raw juice in sugarcane processing on the juice quality and sucrose loss was investigated. Alum was incorporated in both intermediate and hot liming clarification processes of cane juicing. One portion of the cane juice was used for With Pre-treatment Treatment (WPT) while the other portion constituted No Pre-treatment (NPT) juice. Alum at levels of 0 mg L-1, 50 mg L-1, 100 mg L-1 and 150 mg L-1 was incorporated in both intermediate and hot liming clarification processes in each of the two cane juice portions. Sugar concentration (sucrose, glucose and fructose), oBrix, pH, colour, settling performance (initial settling rates (ISR), final mud volume (MV∞), and turbidity) and residual aluminium ion concentration were evaluated. Any significant variations (p < 0.05) in these parameters were assessed. The study found significantly lower (p < 0.05) sucrose losses in clarified juice from intermediate liming of WPT after alum treatment than in the rest of the clarified juices. Colour and turbidity in the pre-treated cane juice of intermediate liming was reduced by 36.9% and 98.1%, respectively at 150 mg L-1 alum level. An initial settling rate of 260 mL min-1 in WPT cane juice of intermediate liming at 150 mg L-1 alum level resulted in the most compact final mud volume of 10.3%. The residual aluminium concentration (0.025 to 0.048 mg L-1) in alum treated clarified juices was lower than the natural aluminium concentration (0.088 mg L-1) in untreated cane juice. This study showed the potential for the use of alum in cane juice clarification to improve on clarification efficiency and lower sucrose loss.
Benard M. Kimatu, Symon Maina Mahungu, Abdul K. Faraj, Symon M. Mahungu, Benard Muinde Kimatu
01.12.2014.
Professional 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/Caco-2 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-a 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 non-dairy 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 Cháfer, Amparo Chiralt, Jose Moisés Laparra, Chelo González-Martínez
01.12.2014.
Professional paper
Training requirements for agro-food industry in Portugal
Agro-food companies are aware that the technical and soft skills of their employees directly influence business performance and, consequently, improving those skills will enhance the effectiveness and efficiency of their companies. This paper presents the main results of the AgriTraining project “Training requirements for the agro-food industry". Activities in pursuit of the objectives of this project involved: (1) analysis of the training needs in the agro-food industry in Portugal; (2) analysis of the training provision and the training organizations; (3) analysis of market trends; (4) definition of a training strategy; and (5) adjustment and development of training strategies for the agro-food sector. This last activity comprised the development of training curricula, suitable for the food sector as a whole and adjusted for the specific needs of some traditional industries, in order to promote the development and competitiveness of the agro-food industry in Portugal. Such training curricula aimed to promote the uptake of innovative technologies and methodologies, increase the ability of agro-food industries to invest and take risks, and enable adoption of European Community standards for production and marketing. Gaps in training supply were identified and the training provision was updated according to the needs of the agro-food companies. It was determined that companies need and demand knowledge and innovation to increase their competitive position for internationalization purposes. It was possible to define a training strategy based on market-orientation for agro-food differentiation.
Pedro D. Gaspar, Rita Pinheiro, Cláudia Domingues, Celestino Almeida, Teresa Paiva, Carlos D. Pereira, Manuela Vaz-Velho
01.12.2014.
Professional 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 Naïtali
18.10.2014.
Original scientific paper
Variation of physicochemical and sensory properties during the aging of yerba mate
Yerba mate infusion is widely consumed in Argentina, Brazil and Paraguay. One of the processing steps used in Argentina is aging. The following three methods were used to age yerba mate: 1) air humidity and temperature-controlled aging; 2) temperature-controlled aging and 3) no control. The aim of this research was to determine the physicochemical and sensory attribute differences when yerba mate was aged using these three methods. The concentration of caffeine, glucose, fructose, maltose and phenolic compounds and pH diminished in all three aging methods but by different percentages. The sensory attributes did not exhibit uniform behaviour. Astringency remained constant in the first method and diminished in the other two. Bitterness increased in all three methods but by different percentages. Sweetness diminished in all three methods. Notably few correlations were determined between physicochemical and sensory attributes.
Santiago A. Holowaty, Sergio A. Surkan, Valeria D. Trela, German D. Byczko, Miguel E. Schmalko
18.04.2014.
Original scientific paper
Effect of protease inhibitors on thermal gelation of squid (Illex argentinus). mantle paste
The characteristics of the thermal gelation of squid mantle paste and the effect of protease inhibitors on them were investigated. Pastes in the absence and presence the protease inhibitors, ethylendiaminetetracetic acid (EDTA) and phenylmethylsulfonyl fluoride (PMSF), were formulated. Pastes were made by the respective one or two step thermal treatments: direct heating at 85°C for 20 min and preincubation at 27 or 40 °C for 3 or 2 hours, followed by heating at 85 °C for 20 min. The gel strength, water holding capacity (WHC) and whiteness of gelled pastes were analyzed. The tricloroacetic acid (TCA) soluble peptides in homogenate of the muscle were determined. Gel strength decreased when heating was made in two steps. EDTA and PMSF were effective in avoiding that decrease when pre-incubation was made at 40 °C. Maximum gel strength was observed for the gels in presence of EDTA, giving values of 255 and 219 g x cm for the samples made by direct heating and pre-incubated at 40 °C respectively. TCA soluble peptides increased between 20 and 60 °C, with maximum values reached at 30 and 60 °C. No significant differences (p>0.05) were observed in gel whiteness, neither with the thermal treatment nor with the inhibitors. The WHC was higher (p<0.05) in the gelated paste formulated with EDTA. These results show a good gelation capacity of I argentinus pastes and improvements with protease inhibitors.
Maria Elida Paredi, Emilio Aldo Manca, Marcos Crupkin
18.10.2014.
Original scientific paper
Functional properties of proteins isolated from industrially produced sunflower meal
Protein isolate 1 (PI1) and protein isolate 2 (PI2) were prepared from industrially produced sunflower meal by using isoelectric and ethanol precipitation respectively. The water absorption capacity of PI1 was 6 times higher than that of PI2 and was significantly reduced by the presence of 0.03 M and 0.25 M NaCl. Oil absorption capacity of both protein isolates was not influenced by NaCl supplementation. Foam capacity of PI1 and PI2 was pH-dependent. While the foam capacity of both isolates was improved by either 0.03 M or 0.25 M NaCl, the foam stability was negatively influenced by the addition of NaCl at all pH values with except for pH 4. Emulsifying activity of PI1 and PI2 was lowest at pH 4. The emulsions exhibited relatively high stability (> 90%) under all studied conditions. Knowledge of the influence of pH and boundary concentrations of NaCl on the functionality of sunflower meal protein isolates could be beneficial for their future potential application in food industry.
Petia Ivanova, Vesela Chalova, Lidia Koleva
01.12.2013.
Professional 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 99oC 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.
Inês Nunes Ramos, Teresa R.S. Brandão, Cristina L.M. Silva
