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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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01.12.2012.

Professional paper

Antioxidants, their properties, uses in food products and their legal implications

Oxidation decreases consumer acceptability of food by changing its organoleptic properties, destroying essential nutrients and producing toxic compounds. Antioxidants delay oxidation of lipids in foods as well in human systems. Studies reveal that synthetic antioxidants may trigger diseases in human when consumed over a certain concentration. The toxicological effects of synthetic food antioxidants have been the focus of controversy in recent years. There is scope to use natural antioxidants, present in many components of food and plant sources, as a preservative. In this review different synthetic and natural antioxidants present in various foods, reactions with food and the biological system, extraction techniques and their pitfalls as well as legal implication are discussed.

Indrajit D. Thorat, Dipali D. Jagtap, Debabandya Mohapatra, D. C. Joshi, R. F. Sutar, S. S. Kapdi

18.10.2013.

Original scientific paper

Physicochemical characterization of Gozitan Honey

Honey quality is clearly defined in the EU Directive 2001/110/EC, and by Codex Alimentarius (Codex Stan 12-1981) and the International Honey Commission (IHC, 2002). Our investigation aimed to characterize the physicochemical properties of honey produced on a small island, Gozo which is situated near Malta.  Ten randomly collected honey samples were analysed for moisture content, pH, free acidity, water insoluble content, hydroxymethylfurfural (HMF) content and total phenolic compounds.  Moisture content, pH, free acidity, water insoluble content, and HMF content were within the range specified in standards but the electrical conductivity was generally higher than 0.800 mS cm-1. This may be the result of the relatively high atmospheric and soil salinity on this small island. All the samples analysed were within the 40 mg kg-1 HMF limit, which is an indicator of honey quality. The total phenolic compounds, which represent some of the constituents derived from the nectar and pollen obtained during foraging, ranged between 236.555 and 294.209 GAE kg-1 honey. Principal Component Analysis showed the properties of polyfloral honey samples obtained from the southern part of the island to be different from those obtained from the northern part.

Everaldo Attard, Joseph Mizzi

01.12.2012.

Professional paper

Effect of antioxidant and optimal antimicrobial mixtures of carvacrol, grape seed extract and chitosan on different spoilage microorganisms and their application as coatings on different food matrices

There is growing interest in the use of natural agents with antimicrobial (AM) and antioxidant (AOX) properties. Optimization of the AM capacity for mixtures containing carvacrol, grape seed extract (GSE) and chitosan, against gram-negative (Pseudomonas aeruginosa), gram-positive bacteria (Staphylococcus aureus, Listeria innocua and Enterococcus faecalis) and yeast (Saccharomyces cerevisiae) at 106 cfu mL-1 was studied. To observe the synergistic or antagonistic effect and find optimal combinations between the three agents, a simplex centroid mixture design was run for each microorganism, combining carvacrol (0-300 ppm, X1), GSE (0-2000 ppm, X2) and chitosan (0-2% w/v, X3). Results of the response surface analysis showed several synergistic effects for all microorganisms. Combinations of 60 ppm-400 ppm-1.2% w/v (carvacrol-GSE-chitosan; optimal AM combination 1, OAMC-1); 9.6 ppm-684 ppm-1.25% w/v (OAMC-2); 90 ppm-160 ppm-1.24% w/v (OAMC-3) were found to be the optimal mixtures for all microorganisms. Radical scavenging activity (RSA) of the same agents was then compared with a standard AOX (butylated hydroxytoluene; BHT) at different concentrations (25, 50 and 100 ppm; as well as the optimal AM concentrations) by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) method. RSA increased in the following order: chitosan< carvacrol< BHT< GSE and for the OAMC: OAMC-2< OAMC-1< OAMC-3. The best RSA (OAMC-3) was applied as a coating in two different food matrices (strawberries and salmon). For strawberries, P. aeruginosa was more sensitive to the action of OAMC-3 than S. cerevisiae. For salmon, S. aureus was more resistant to the action of OAMC-3 than E. faecalis and L. innocua.

Javiera F. Rubilar, Rui M.S. Cruz, Igor Khmelinskii, Margarida Cortez Vieira

18.10.2013.

Original scientific paper

Effects of modified atmosphere, associated with masterpack transport packaging, and refrigerated storage time on the quality characteristics of pork loin cuts

The objective of this research was to study the effects of modified atmosphere, associated with masterpack transport packaging, and refrigerated storage time on the quality characteristics of pork loin cuts. Cuts of pork loin were packaged in trays, covered with poly(vinyl chloride) film. The trays were placed in a masterpack (MP), containing three gas compositions:  A) 75% O2 : 25% CO2, B) 50% O2 : 50% CO2 or C) 100% CO2, and stored at 2 °C. Samples were taken after 1, 8, 15, and 22 days of storage, and evaluated for numerous shelf life traits. The development of Psychrotrophic aerobic bacteria and Pseudomonas spp. was found from the 15th day of storage. There was a significant treatment effect for some of the considered parameters, such as pH (P < 0.05) and color [L* (P < 0.07), a* (P < 0.07) and b* (P < 0.01)]. There was a significant interaction (P < 0.01) for the TBARS values. It can be concluded, from the microbiological point of view, that the use of modified atmospheres containing 25% to 100% CO2 promotes the conservation of meat for up to 15 days of storage under refrigeration. From the point of view of color, atmospheres containing 75% O2 : 25% CO2 and 50% O2 : 50% CO2 ensure the color of packaged pork meat when stored at 2 °C for up to 15 days. From the point of view of lipid oxidation, packages with 100% CO2 are recommended for storage periods of more than 15 days, whereas those with 75% O2 : 25% CO2 are recommended for storage periods of up to 8 days.

Alessandra Rosa, Mirele D. Poleti, Julio C.C. Balieiro, Marcelo C. César, Paulo J.A. Sobral

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

01.12.2012.

Professional 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

Profile of currently employed European Food Scientists and Technologists: Education, experience and skills

The food & drink (F&D) sector in Europe ranks low in innovation and the European F&D industry has been losing importance in the global market. The food professionals, i.e., food scientists and technologists (FSTs), may not be meeting the varied demands of the sector. Here, we identify education, experience and skills of current FSTs and compare  geographic regions and employment areas. Between 2009 and 2012, 287 questionnaires representing over 4000 FSTs were collected from employers in 16 countries. Analyses showed that more than 80% of FSTs have a university degree; but only in Industry in the Central European region are most degrees in food science/technology. More than half of FSTs, and almost 60% in the South, have less than 10 years’ experience. The most common FST job title is Quality Manager, but with several variations based on region and employment area. Among skills, the most common is Communicating; found in over 90% of FSTs in all regions and employment areas. Food Safety is the most common of the food sector-specific skills, present in more than 75% of FSTs, yet there are differences in food sector skills based on employment area. Overall, these data suggest similarities among currently employed food professionals throughout Europe; they are young and highly educated, but also differences, especially in their food sector-specific skills. An understanding of the current FST should contribute to the improvement of FST training and thus benefit the European food sector.

Katherine Flynn, Barbara Ruiz Bejarano, Erik Wahnstrom, Camelia Echim, Mafalda A.C. Quintas

18.10.2013.

Original scientific paper

Use of response surface methodology to evaluate the reducing power in binary solutions of ascorbic acid with natural polyphenolic antioxidants

Natural polyphenols, ferulic acid (FA) and hesperetin (Hp) were tested for their Fe3+-reducing power, using the TPTZ methodology, as a first step to rank them according to their antioxidant potential. Ranking also included quercetin (Qt), a very well-studied natural, polyphenolic antioxidant, and ascorbic acid (AA). All phenolics considered were also tested in binary mixtures with AA, to illustrate possible mixture effects. By employing a simple linear regression approach, combinations of AA / Qt and AA / Hp were shown to result in antagonistic effects, whereas in mixtures of AA / FA, synergism was observed. To thoroughly investigate the role of the relative concentrations of the antioxidants, a 3×3 factorial design was implemented. This approach enabled the recording of the response (reducing power) upon simultaneous variation of concentrations of both antioxidants in the mixtures, and revealed only antagonism for every combination tested. It is proposed that in similar investigations factorial designs need to be implemented for reliable prediction of the antioxidant response(s) within appropriate limits. This is particularly crucial for antioxidants that are destined to be added in food matrices, where maximal antioxidant protection is always sought.

Marie Aoun, Dimitris Makris

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

18.10.2013.

Original scientific paper

Mechanical properties of rough and dehulled rice during drying

This work aimed to determine the mechanical properties of rough and dehulled rice grains, for different moisture contents, by obtaining their rupture force, deformation, maximum compression force and proportional deformity modulus under a compression test. Rice grains, with moisture content varying from 0.12 to 0.30 (d.b.), were subject to an uniaxial compression in order to analyze these properties. On reducting moisture content the rupture force increased from 37.2 to 70.6 N for dehulled rice and 48.0 to 79.5 N for rough rice. The average compression force varied from 131 to 171 N for dehulled rice and 203 to 283 N for rough rice. The value range of proportional deformity modulus was from 5.5 x 109 to 7.4 x 109 Pa for dehulled rice and 9.5 x 109 to 12.3 x 109 Pa for rough rice. Rough rice presented more resistance to compression compared to dehulled rice.

Osvaldo Resende, Paulo César Corrêa, Gabriel Oliveira, André Luis Duarte Goneli, Carmen Jarén

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