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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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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

18.10.2014.

Original scientific 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.

Jacopo Mistrello, Sameera Dewundara Sirisena, Abdollah Ghavami, Richard James Marshall, Suresh Krishnamoorthy

01.12.2013.

Professional 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 Ivanova Chalova, Lidia Koleva

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

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 4th 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.

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

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

18.04.2014.

Original scientific 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

18.04.2014.

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

18.04.2014.

Original scientific paper

Popping characteristics of paddy using microwave energy and optimization of process parameters

Microwave popping characteristics of a particular variety of paddy were studied using a domestic microwave oven. The experiments were carried out at 4 levels of moisture content (around 13%, 14%, 15% and 16% wb), 3 levels of power (600 W, 850 W and 1000 W) and 5 levels of heating time (40 s, 60 s, 80 s, 100 s and 120 s). A general factorial experiment design was followed, and effect of different treatment combinations on popping percentage and expansion ratio of the paddy was evaluated. The maximum popping percentage of 63.47% was obtained at a moisture content of 14.15% and energy level of 80 kJ (1000 W and 80 s) while the maximum expansion ratio of 4.42 was obtained at 14.94% moisture content and energy level of 68 kJ (850 W and 80 s). Optimum values of microwave power, time of heating and moisture content of paddy were achieved at 1000 W, 80 s and 15%, respectively, corresponding to popping percentage and expansion ratio of 58.73 and 3.58.

Ajay Kumar Swarnakar, M. Kalpana Devi, Susanta Das

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

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