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Volume 14, Issue 1, 2025

Online ISSN: 2182-1054

Volume 14 , Issue 1, (2025)

Published: 31.07.2025.

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18.10.2014.

Original scientific paper

Blast-cooling of beef-in-sauce catering meals: numerical results based on a dynamic zero-order model

Beef-in-sauce catering meals under blast-cooling have been investigated in a research project which aims at quantitative HACCP (hazard analysis critical control point). In view of its prospective coupling to a predictive microbiology model proposed in the project, zero-order spatial dependence has proved to suitably predict meal temperatures in response to temperature variations in the cooling air. This approach has modelled heat transfer rates via the a priori unknown convective coefficient hc which is allowed to vary due to uncertainty and variability in the actual modus operandi of the chosen case study hospital kitchen. Implemented in MS Excel®, the numerical procedure has successfully combined the 4
th order Runge-Kutta method, to solve the governing equation, with non-linear optimization, via the built-in Solver, to determine the coefficient hc. In this work, the coefficient hc was assessed for 119 distinct recently-cooked meal samples whose temperature-time profiles were recorded in situ after 17 technical visits to the hospital kitchen over a year. The average value and standard deviation results were hc = 12.0 ± 4.1 W m−2 K −1 , whilst the lowest values (associated with the worst cooling scenarios) were about hc ≈ 6.0 W m−2 K −1 .Convective heat transfer

Jose Rabi, Evelyne Derens-Bertheau, Elisabeth Morelli, Isabelle Trezzani-Harbelot

18.04.2014.

Original scientific paper

The Regulation of Food Science and Technology Professions in Europe

The regulation of a profession is justified when it improves consumer protection and public health. Higher education food science and technology (FST) degrees, widely offered in many universities in Europe open to a wide range of jobs in the food sectors where the employees could cover different positions, roles and carry out diverse activities dealing with the food production and the quality and safety of the food products.This work reviews the state of the art of the FST regulated professions requiring higher education qualifications in the European countries. The research was carried out by collecting specific information on regulated professions by contacting unions, professional associations, public servant categories/professions, and by visiting national and EU websites.  The data collected for each regulated profession were: country, training/education required, date of implementation of regulation, professional training (if required), capability test (if required) and acts required by law to be signed by a regulated professional. Only professions that required a higher education diploma were included in this search.Few countries were found to have a regulated profession in FST, in particular: Food Engineering (Turkey), Food Technologist (Greece, Iceland, Italy and Slovenia), and Oenologist (Italy, Portugal and Spain). FST regulated professions in Europe are thus scarce and have a rather limited history. The Food Technologist in Italy and the Food Engineer in Turkey were found to be the only completely regulated professions found in Europe. Food and professional regulation have been evolved over the years and raised the debate on the regulation of FST professions. Academia as well as other policymakers has to further contribute to this discussion to keep high the standards for quality of education and training of the qualified workforce and professionals in the food sector.

Rui Costa, Sonja Smole Možina, Paola Pittia

01.12.2013.

Professional 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.

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

01.12.2013.

Professional paper

Stability of cupuaçu (Theobroma grandiflorum) nectar during storage

A shelf-life study on cupuaçu 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 (TTS), 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, kAA(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, kAA(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 Cortez Vieira, Cristina L.M. Silva

01.12.2013.

Professional paper

Characterization of potent odorant compounds in Turkish olive oils by GC-MS-olfactometric techniques

The purpose of this study was to determine the most powerful aroma-active compounds of olive oils obtained from Ayvalik (AYV), Gemlik (GEM) and Memecik (MEM) cultivars harvested in 2011, using gas chromatography-mass spectrometry-olfactometry (GC-MS-O). Simultaneous distillation and extraction (SDE) with dichloromethane was used for extraction of volatile components. The aroma-active compounds of olive oils were evaluated by aroma extract dilution analysis (AEDA). A total of 14, 12 and 12 aroma-active compounds within the range of ≥64–1024 flavor dilution (FD) factors were detected in aromatic extracts of olive oils obtained from AYV, GEM and MEM cvs., respectively. The compounds having the highest FD factor (1024) were (Z)-3-hexenol (cut grass, herbal) and β-sesquiphellandrene (floral) for AYV oil and (Z)-3-hexenyl acetate (fruity) for MEM oil. Among these compounds, terpenes were the overwhelmingly largest aroma-active components followed by aldehydes.

Songul Kesen, Hasim Kelebek, Serkan Selli

01.12.2013.

Professional paper

Vegetable milks and their fermented derivative products

The so-called vegetable milks are in the spotlight thanks to their lactose-free, animal protein-free and cholesterol-free features which fit well with the current demand for healthy food products. Nevertheless, and with the exception of soya, little information is available about these types of milks and their derivatives. The aims of this review, therefore, are to: highlight the main nutritional benefits of the nut and cereal vegetable milks available on the market, fermented or not; describe the basic processing steps involved in their manufacturing process; and analyze the major problems affecting their overall quality, together with the current feasible solutions. On the basis of the information gathered, vegetable milks and their derivatives have excellent nutritional properties which provide them a high potential and positive market expectation. Nevertheless, optimal processing conditions for each raw material or the application of new technologies have to be researched in order to improve the quality of the products. Hence, further studies need to be developed to ensure the physical stability of the products throughout their whole shelf-life. These studies would also allow for a reduction in the amount of additives (hydrocolloids and/or emulsifiers) and thus reduce the cost of the products. In the particular case of fermented products, the use of starters which are able to both improve the quality (by synthesizing enhanced flavors and providing optimal textures) and exert health benefits for consumers (i.e. probiotics) is the main challenge to be faced in future studies.

Neus Bernat, Maite Cháfer, Amparo Chiralt, Chelo González-Martínez

01.12.2013.

Professional paper

Effects of Lactic Acid Fermentation on the Retention of Β-Carotene Content in Orange Fleshed Sweet Potatoes

This study aimed to establish the effects of lactic fermentation on the levels of β-carotene in selected  orange fleshed sweet potato (OFSP) varieties from Kenya.  Furthermore,it sought to demonstrate fermentation as a potential process for making new products from sweet potato with enhanced nutraceutical attributes. The varieties (Zapallo, Nyathiodiewo and SPK004/06) were fermented with Lactobacillus plantarum MTCC 1407 at 25 ± 2°C for 48 h and kept for 28 days to make lacto-pickles. During fermentation both analytical [pH, titratable acidity (TA), lactic acid (LA), starch, total sugar, reducing sugar (g/kg roots), texture (N/m2), β-carotene (mg/kg roots)] and sensory (texture, taste, flavour and after taste) attributes of sweet potato lacto-juice were evaluated. Process conditions were optimized by varying brine levels, with fermentation time. A UV-visible spectrophotometer was used to identify and quantify β-carotene. Any significant variations (p < 0.05) in analytical attributes between the fermented and unfermented samples (pH, LA, TA and β-carotene concentration) of lacto-pickles, prepared from the potato roots, were assessed. The study reported a final composition of 156.49mg/kg, 0.53mg/kg, 0.3N/m2, 1.3g/kg, 5.86g/kg, 0.5g/kg and 5.86g/kg for β-carotene, Ascorbic acid, texture; Starch, total sugars, LA and TA respectively, and a pH of 3.27. The fermented products were subjected to flavour profiling by a panel. The product sensory scores were 1.5 to 2.5 on a 5 point hedonic scale, ranging from dislike slightly to like much. The products with brine levels at 4 and 6% were most preferred. The retention of β-carotene was 93.97%. This demonstrated lactic acid fermentation as a better method for processing OFSP as the main nutritional attributes are retained. The final product was resistant to spoilage microorganisms after 28 days of fermentation. Further preservation could be obtained by addition of sodium metabisulphite. In conclusion, Lactic acid fermentation using L. plantarum is a novel method of producing Lacto pickles from Zapallo OFSP, with 93.97% β-carotene retention and adequate shelf life.

Benard O. Oloo, A. A. Shitandi, S. Mahungu, J. B. Malinga, Rose B. Ogata

18.04.2013.

Original scientific paper

Increase of “Umami” and “Kokumi” Compounds in Miso, Fermented Soybeans, by the Addition of Bacterial γ-Glutamyltranspeptidase

γ-Glutamyltranspeptidase (GGT) hydrolyzes γ-glutamyl compounds and transfers their γ-glutamyl moieties to amino acids and peptides.  We previously showed that the “umami” taste of soy sauce could be improved by the addition of salt-tolerant Bacillus subtilis GGT to the fermentation mixture, “moromi”.  Although miso fermentation is a semi-solid fermentation, unlike soy sauce fermentation, this was also the case. When 15 units of purified B. subtilis GGT were added to 418 g miso “moromi” (fermentation mixture), the glutamate concentration in “moromi” became 20 mM higher and the “umami” taste became stronger than without the addition of GGT after 2 to 6 months of fermentation.  In addition, γ-Glu-Val and γ-Glu-Val-Gly, which are known as “kokumi” peptides, were identified in “tamari”, and the concentrations of these γ-glutamyl peptides in “tamari" fermented by the addition of GGT were significantly higher than those of “moromi” without the addition of GGT.  These results indicate that B. subtilis GGT is able to improve the taste of miso.

Thao Van Ho, Hideyuki Suzuki

18.10.2013.

Original scientific paper

Effect of antimicrobial on mechanical, barrier and optical properties of corn starch based self-supporting edible film

Antimicrobials like potassium sorbate, sodium propionate, and benzoic acid were incorporated in corn starch based formulation to investigate their effect on mechanical, water vapour barrier and optical properties of the developed self supporting edible film. The film was prepared by casting technique.When incorporated at 1.40% and above, potassium sorbate decreased the tensile strength (about 22%) and increased the elongation (about 55%) of control film; whereas, it increased the water vapour permeability by 15% only when added at 2.66%. At 2.66%, benzoic acid reduced the tensile strength by 24% and sodium propionate increased elongation by 17%. These two antimicrobials did not change the water vapour permeability. However, all the three antimicrobials adversely affected the optical properties by decreasing the whiteness index, increasing yellowness index, and reducing the surface gloss, with potassium sorbate showing the maximum effect. Among the three antimicrobials, sodium propionate appeared to be the best with minimum deterioration of film properties.

Tanima Chowdhury, Madhusweta Das

01.12.2012.

Professional paper

The impact of cold chain temperature abuses on the quality of frozen strawberries (Fragaria ×ananassa)

The quality of frozen foods can be negatively affected if improper storage and distribution temperatures are allowed. The objective of this study was to investigate the effect of freeze-thaw cycles, which may occur in the cold chain, on colour (Lab, Total Colour Differences (TCD), chroma and hue angle) and vitamin C (ascorbic and dehydroascorbic acids) content of frozen strawberries (Fragaria ×ananassa, Duschesne, cv. Selva). A plan of temperature abuses (TAs) was established, based on a real situation, and applied to frozen strawberries during a four month frozen storage period. The results showed that the lightness (L) was the only parameter that was not significantly affected by range of TAs studied. The colour showed some variation on the parameters a, b, TCD, chroma and hue angle. During TAs, ascorbic acid decreased about 75% and dehydroascorbic acid increased 73%. The non-abused strawberry samples showed better overall appearance than the abused samples.This work contributes to an understanding of the quality changes of frozen strawberries that might occur during frozen storage and cold chain distribution.

Rui Cruz, Margarida Vieira, Cristina Silva

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