Contents
01.12.2015.
Professional paper
Natural antioxidants isolated from Schinus areira leaves by ultrasound-assisted extraction
The aim of this study was to optimize the extraction of antioxidant compounds from Schinus areira leaves using ultrasound assisted extraction and response surface methodology. The effect of sonication time and plant material:solvent ratio were used to optimize the recovery. Results showed that a high recovery of antioxidant compounds from leaves of three different S. areira specimens was achieved under optimized conditions. The leaf extracts obtained displayed a DPPH (1,1-Diphenyl-2-picrylhydrazyl) radical scavenging activity analogous to the well-known antioxidant trolox (EC50 = 23-46 vs 36.1 µg/mL, respectively). In addition, these extracts showed a good potency to eliminate superoxide and nitric oxide-radicals as well as a moderate antimicrobial activity against gram positive Staphylococcus aureus and Enterococcus faecalis and yeast. HPLC chromatography analysis of the three S. areira leaf extracts showed different high contents of kaempferol-3-O-rutinoside, quercetin-3-O-galactoside and 3-O-caffeoylquinic acid. The results showed that the S. areira leaf extracts contained a high amount of antioxidant phenolic compounds, which might be a valuable source to be used as additives in plant-based foods.
Liliana S. Celaya, Carmen I. Viturro, Luís R. Silva, Silvia Moreno
01.12.2015.
Professional paper
Reproducibility and correlation between meat shear force measurements by Warner-Bratzler machine and a texturometer
Tenderness has a prominent position on meat quality and is considered to be the sensory characteristic that most influences meat acceptance. Therefore, the aim of this study was to evaluate the accuracy and determine correlations among three different meat shear force techniques. Commercial samples of bovine Longissimus thoracis et lumborum (BLTL), Tensor fasciae latae (BTFL), Semitendinosus (BST), Psoas major (BPM), Biceps femoris (BBF) and swine Longissimus thoracis et lumborum (PLTL) were analyzed for pH, proximate composition, cooking loss and shear force with a classical Warner-Bratzler device and a TA-XT2 Texturometer equipped with shear blades 1 and 3 mm thick. The effect of different techniques in each studied muscle was statistically analyzed and regression curves were built. Results from the 1 mm blade were quite similar to the ones obtained with the Warner-Bratzler, however the results from 3 mm blade were overestimated (p<0.05). Significant correlation (p<0.01) among shear force technique using Warner-Bratzler and the ones using the Texturometer was observed (0.47 for 1 mm blade and 0.57 for the 3 mm blade). In conclusion, we found that the 1 mm blade and the Warner-Bratzler machine are reproducible for all tested muscles, while the 3 mm blade is not reproducible for the BTFL, BST, BPM, BBF, PLTL. There is a significant correlation between the results obtained by the classical Warner-Bratzler and the TA-XT2 Texturometer equipped with both blades. Therefore, TA-XT2 Texturometer equipped with the 1mm blade can perfectly replace the traditional Warner-Bratzler device.
Lucas Arantes-Pereira, Flávia C. Vargas, Júlio C.C. Balieiro, Ana Monica Q.B. Bittante, Paulo J.A. Sobral
01.12.2015.
Professional paper
Modeling the kinetics of peroxidase inactivation, colour and texture changes of Portuguese cabbage (Brassica oleracea L. var. costata DC) during UV-C light and heat blanching
The effects of heat blanching and UV-C light followed by heat on Portuguese cabbage peroxidase (POD), colour and texture were studied in the temperature range of 80-95 °C. POD inactivation, lightness (L) and yellowness (b) colour changes were described by a first-order reaction model. The greenness (a) colour and texture (firmness) changes followed a two fraction kinetic model behaviour. The temperature effect was well described by the Arrhenius law.At lower temperatures the combined treatment showed higher POD inactivation. Colour and texture parameters did not show significant differences between treatments. Long processing times turned the leaves slightly darker, decreased greenness, yellowness and firmness. Short processing times increased the firmness and greenness of the leaves. The treatment at 80 °C for 90 seconds reduced 90% of POD, retaining 98% of lightness and 92% of yellowness and improved the green colour (130%) and firmness (125%). At 80 °C the heat blanching required 7.4 min to inactivate 90% of the enzyme activity, reducing lightness, greenness, yellowness and firmness to 92%, 68%, 62% and 61%, respectively. The present findings will help to optimize the Portuguese cabbage blanching conditions.
Rui M.S. Cruz, Ana I.A. Godinho, Dilek Aslan, Necip F. Koçak, Margarida C. Vieira
01.12.2015.
Professional paper
Bioactive components, antioxidative properties and inhibition of Fe2+-induced lipid peroxidation of mango peel as affected by the storage of mango fruit
This study sought to evaluate the bioactive components (total phenolics, vitamin C and flavonoid), antioxidant properties (FRAP, and hydroxyl, DPPH and ABTS radical scavenging abilities) and inhibition of Fe2+-induced lipid peroxidation of the peel of mango fruit stored at refrigeration temperature and room temperature. The peel of mango fruit stored at room temperature had significantly (P ≤ 0.05) higher contents of total phenolic (13.61 mg GAE/g), vitamin C (12.98 mg AAE/g), total flavonoid (4.49 mg QE/g) and non-flavonoid (9.12 mg Qe/g) than the peel of freshly harvested mango fruit and the peel of mango fruit stored at refrigeration temperature. In consonance with the bioactive components, the peel of mango fruit stored at room temperature had a higher FRAP, and hydroxyl, DPPH and ABTS radical scavenging abilities than the others. The peel of mango fruit stored at room temperature showed stronger inhibition of Fe2+ induced lipid peroxidation by exhibiting the least IC50 (1.44 mg/ml in brain), (1.43 mg/ml in pancreas) and (1.88 mg/ml in kidney). Thus freshly harvested, matured, edible and just ripe mango fruit (Sheri Mango) could be stored at room temperature and be consumed with the peel.
Adetuyi O. Foluso, Akinlerye Makinde, Ifedayo Adeyemi, Victoria Timothy
01.12.2015.
Professional paper
Effect of roasting regime on phytochemical properties of Senna occidentalis seeds
Senna occidentalis seeds were roasted at varying temperatures of 190, 210 and 230 oC each for 10, 15 and 20 min. Phytochemicals of the roasted seeds were determined using standard methods. The phytochemicals analysed were tannins, saponins, flavonoids, alkaloids, glycosides, oxalate and phenolics. Phytochemicals are compounds hypothesized for much of the disease-protection provided by diets high in fruits, vegetables, legumes, cereals and plant-based beverages. This study has clearly shown that roasting time and temperature have significant effects on the seed parameters analyzed. There was an increase in tannin, alkaloid, saponin and phenolic contents and a decrease in the contents of flavonoids and oxalates.
Abiodun A. Olapade, Oreofeoluwatomi A. Ajayi
01.12.2015.
Professional paper
Assessment of nutritional composition in elephant foot yam (Amorphophallus paeoniifolius Dennst- Nicolson) cultivars
Elephant foot yams make a significant contribution to diets in tribal people of India. However, there is insufficient study of their nutritional and antioxidant value. In this paper the various traits of eleven cultivars of elephant foot yam: BCA-1, BCA-2, BCA-4, BCA-5, BCA-6, NDA-4, NDA-5, NDA-9, IGAM-1, AC-28 and Gajendra were studied and observed during the growth and development stage. The cultivar of BCA-6 contained the maximum amount of starch and total phenol at 100 Days After Planting (DAP) while cv., NDA-9 and NDA-5 showed the maximum content of starch and total phenol at 250 DAP respectively. However, the cultivar BCA-1 stored the maximum amount of carbohydrate at 100 DAP whereas ascorbic acid and β-carotene content was highest at 250 DAP. The protein amount was maximum in cv., BCA-2 and AC-28 at 100 and 250 DAP respectively. This information will provide breeders with the ability to develop desirable types of elephant foot yams having high yields and better nutritional profiles.
Amit Singh, Arvind Chaurasiya, Surajit Mitra
01.12.2015.
Professional paper
Solubility of Stevioside and Rebaudioside A in water, ethanol and their binary mixtures
In order to investigate the solubility of Stevioside and Rebaudioside A in different solvents (ethanol, water, ethanol:water 30:70 and ethanol:water 70:30), supersaturated solutions of pre-crystalized steviol glycosides were maintained at different temperatures (from 5 °C to 50 °C) to reach equilibrium. Under these conditions significant differences were found in the extent of solubility. Rebaudioside A was poorly soluble in ethanol and water, and Stevioside was poorly soluble in water. Solvent mixtures more effectively promoted solubilisation, and a significant effect of temperature on solubility was observed. The two steviol glycosides showed higher solubilities and this behavior was promoted by the presence of the other sweetener. The polarity indices of the solvents were determined, and helped to explain the observed behavior. Several solute-solvent and solute-solute interactions can occur, along with the incidence of a strong affinity between solvents. The obtained results are in accordance with technological applications of ethanol, water and their binary mixtures for Stevioside and Rebaudioside A separations.
Liliana S. Celaya, Eugenio Kolb, Nicolás Kolb
18.04.2015.
Original scientific paper
Enhancing food engineering education with interactive web-based simulations
In the traditional deductive approach in teaching any engineering topic, teachers would first expose students to the derivation of the equations that govern the behavior of a physical system and then demonstrate the use of equations through a limited number of textbook examples. This methodology, however, is rarely adequate to unmask the cause-effect and quantitative relationships between the system variables that the equations embody. Web-based simulation, which is the integration of simulation and internet technologies, has the potential to enhance the learning experience by offering an interactive and easily accessible platform for quick and effortless experimentation with physical phenomena. This paper presents the design and development of a web-based platform for teaching basic food engineering phenomena to food technology students. The platform contains a variety of modules (“virtual experiments”) covering the topics of mass and energy balances, fluid mechanics and heat transfer. In this paper, the design and development of three modules for mass balances and heat transfer is presented. Each webpage representing an educational module has the following features: visualization of the studied phenomenon through graphs, charts or videos, computation through a mathematical model and experimentation. The student is allowed to edit key parameters of the phenomenon and observe the effect of these changes on the outputs. Experimentation can be done in a free or guided fashion with a set of prefabricated examples that students can run and self-test their knowledge by answering multiple-choice questions.
Alexandros Koulouris, Georgios Aroutidis, Dimitris Vardalis, Petros Giannoulis, Paraskevi Karakosta
18.04.2015.
Original scientific paper
A methodology to promote business development from research outcomes in food science and technology
Valorization of knowledge produced in research units has been a major challenge for research universities in contemporary societies. The prevailing forces have led these institutions to develop a “third mission”, the facilitation of technology transfer and activity in an entrepreneurial paradigm. Effective management of challenges encountered in the development of academic entrepreneurship and the associated valorization of knowledge produced by universities are major factors to bridge the gap between research and innovation in Europe. The need to improve the existing institutional knowledge valorization processes, concerning entrepreneurship and business development and the processes required were discussed. A case study was designed to describe the institutional knowledge valorization process in a food science and technology research unit and a related incubator, during a five year evaluation period that ended in 2012. The knowledge valorization processes benefited from the adoption of a structured framework methodology that led to ideas and teams from a business model generation to client development, in parallel, when possible, with an agile product/service development. Although academic entrepreneurship engagement could be improved, this case study demonstrated that stronger skills development was needed to enable the researcher to be more aware of business development fundamentals and therefore contribute to research decisions and the valorisation of individual and institutional knowledge assets. It was noted that the timing for involvement of companies in the research projects or programs varied with the nature of the research.
Eduardo Cardoso
18.04.2015.
Original scientific paper
Sensory evaluation of aromatic foods packed in developed starch based films using fuzzy logic
The last two decades have seen attempts to replace non biodegradable, synthetic food packaging films with alternatives made from biopolymers. The objective of the present work was to evaluate sensory quality of tea leaf and culinary tastemaker powder when sealed in pouches based on starch films. Films were developed from corn starch and a functional polysaccharide (FP) from amylose (AM), methylcellulose (MC), and hydroxypropylmethylcellulose (HPMC), using a casting technique. Pouches were stored inside a secondary package (plastic jar) under ambient condition for 90 days. Sensory attributes of the stored food samples were evaluated (tea in liquor form) and the scores analysed by fuzzy logic. Results were compared with similarly stored foods but using market available poly-pouches as packaging material.
For tea and tastemaker in general, the relative importance of the sensory attributes under consideration was assessed as: aroma (Highly important) > taste (Highly important) > colour (Highly important) > strength (Important) for tea, and taste (Highly important) > aroma (Highly important) > colour (Important) > appearance (Important) for tastemaker. Among the three films that were developed, the highly important sensory attributes of aroma and taste were maintained as ‘Very good’ when the foods were packed in starch–HPMC/AM film. When the products were packed in market-available polypouches they exhibited similar attributes. With the exception of ‘Very good’ maintenance of the colour of tastemaker by the commercial pouch, irrespective of film and food, the colour and strength/appearance were retained in the ‘Good’-‘Satisfactory’ range. The overall sensory score of tea was also maintained as ‘Very good’ in starch-HPMC film.
Tanima Chowdhury, Madhusweta Das