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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
18.10.2014.
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
01.12.2013.
Professional paper
Determination of the antioxidant capacity, total phenolic and flavonoid contents of seeds from three commercial varieties of culinary dates
Date seeds are a major waste product of the date industry that could offer potentially valuable material for the production of useful food ingredients. The aim of the present study was to investigate the seeds of three date varieties of the UK market (Deglet Nour, Khouat Allig, and Zahidi) for their proximate composition, total phenolic (TPC), total flavonoid (TFC) contents and total antioxidant capacity (TAC) with a view to their eventual industrial application. Carbohydrates were present in the highest concentrations varying between 74.13 and 76.54 g 100 g-1 of date seed powder (DSP) on dry weight (DW) basis, followed in descending order by fats (7.64-8.84 g 100 g-1) and proteins (4.35-5.51 g 100 g-1). Potassium was found in high amounts with values ranging between 280.55 and 293.13 mg 100 g-1. The majority of the total phenolic content (2058-2984 mg GAE 100 g-1) was assumed to be composed of flavonoids (1271-1932 mg CAE 100 g-1). These families of dietary phenolics may be the major ones responsible for the high antioxidant capacity reported in date seeds, which varied from 12540 and 27699 µmol TE 100 g-1. These results suggest that date seeds can be considered a potential raw material for natural, active ingredients for food applications as well as an unexplored source of novel nutraceuticals and dietary supplements.
Suresh Krishnamoorthy, Jacopo Mistrello, Sameera Dewundara Sirisena, Abdollah Ghavami, Richard James Marshall
01.12.2013.
Professional paper
The relationship between antibrowning, anti-radical and reducing capacity of Brassica and Allium extracts
Mariela C Bustos, Lina Marcela Agudelo-Laverde, Florencia Mazzobre, Pilar Buera
01.12.2013.
Professional paper
Effect of Buckwheat Processing Products on Dough and Bread Quality Made from Whole-Wheat Flour
The paper gives a brief overview of the current nutritional status of the Ukrainian population and describes useful buckwheat properties. The objective of the paper is to study the effect of buckwheat processing products (flour and flakes) on the technological process and quality of bread made from whole-wheat flour. This paper describes and analyzes research data on the rheological properties of dough samples which were determined by farinograph and amylograph.Investigation of structural and mechanical properties of dough showed an increase in water-absorbing capacity in all samples when adding buckwheat products. Moreover, dough made with buckwheat flakes has a lower value of mixing tolerance index (by 47 %) than dough made from buckwheat flour, and a higher valorimetric value (by 20 %). Determination of dough properties by amylogram has shown that a sample containing buckwheat flakes has a higher maximum viscosity than a sample containing buckwheat flour. Determination of the gas-production and gas-retention capacity of dough is also presented, along with an analysis of the quality of finished products based on the results of laboratory baking tests.The samples of bread supplemented with buckwheat flakes have better shape stability (by 21 %), specific volume (by 12 %) and porosity (by 11 %) than bread made from buckwheat flour. The organoleptic evaluation of finished product quality has shown that bread supplemented with buckwheat flakes has a more fluffy-texture, elastic crumb and uniform porosity than bread made from buckwheat flour. Buckwheat flakes proved to have a better effect on parameters of the technological process and quality of bread when compared with buckwheat flour.
Vira Drobot, Anastasiya Semenova, Jelyzaveta Smirnova, Larisa Mykhonik
01.12.2013.
Professional paper
Peer-teaching in the food chemistry laboratory: student-produced experiments, peer and audio feedback, and integration of employability skills
Julie Lisa Dunne
01.12.2013.
Professional paper
Fermentation and antimicrobial characteristics of Lactobacillus plantarum and Candida tropicalis from Nigerian fermented maize (akamu)
Patience Chisa Obinna-Echem, Victor Kuri, Jane Beal
01.12.2013.
Professional paper
PhD competences of food studies
Chelo Gonzalez-Martinez, Cristina LM Silva, Rui Costa