Review Article

Bio-antioxidants Activity: Their Mechanisms and Measurement Methods

M.A Sahari, S Berenji Ardestani

Applied Food Biotechnology, Vol. 2 No. 1 (2015), 19 February 2015, Page 3-8

Bioactive food components (such as phenolic compounds, carotenoids, anthocyanins, tochopherols, ascorbic acid, flavonoids, minerals, enzymes and pectin) are active ingredients in food or dietary supplements, which proven to have an important role in health, and are safe for human consumption. These compounds exert their antioxidant effects by different mechanisms such as single electron transfer or hydrogen atom transfer, and their efficiencies can be evaluated by several methods such as ferric reducing ability of plasma, oxygen radical absorbance capacity assay, total radical trapping antioxidant parameter, total oxidant scavenging capacity, conjugated dienes, lipoxygenase activity inhibition assay, chemiluminescence, deoxyribose, tocopheroxyl radical attenuating ability, and nitric oxide radicals trapping. In this review, these mechanisms and methods will be discussed in details.

Original Article

Compositional Evaluation of Raw and Processed Harms (Brachystegia Eurycoma) Seed Flour

M.O Aremu, I.M Ohale, A.M Magomya, D.B Longbap, O.A Ushie

Applied Food Biotechnology, Vol. 2 No. 1 (2015), 19 February 2015, Page 9-18

Brachystegia eurycoma is predominantly grown in the eastern region of Nigeria. Its seed is used in food majorly as a soup condiment, flavouring agent and soup thickener. The proximate, mineral and amino acid compositions were determined on raw and processed seeds (boiled, fermented and roasted) using standard analytical techniques. The processing methods showed deviations in nutrients from the raw seeds. The crude protein was reduced by the processing methods with exception of roasting method. Crude fat was reduced in all the processing methods in this order: Raw > fermented > roasted > boiled samples. All the processing methods enhanced calcium content in this order: Raw < boiled < fermented < roasted samples. Boiling and fermenting reduced the content of magnesium by 72.6 and 30.2%, respectively while boiling, fermenting and roasting increased potassium content by 124.5, 12.2 and 120.4%, respectively. Generally, all the samples were found to be a good source of essential minerals and harmful heavy metals such as lead, chromium, arsenic and cadmium were not at detectable range of atomic absorption spectrophotometer. The amino acid profile revealed that amino acids in fermented sample were better concentrated than that of raw and other processed samples. The total essential amino acids (TEAA) ranged from 28.63 g/100g crude protein in roasted sample to 34.79 g/100g crude protein in fermented sample. The limiting amino acid (LAA) for all the samples was Met + Cys (TSAA).

Identification of Anti-microbial Producing Enterococci Isolated from Iranian Raw Milk Cheeses Using Polyphasic Approach

M.R Edalatian, M.B Habibi Najafi, A Mortazavi

Applied Food Biotechnology, Vol. 2 No. 1 (2015), 19 February 2015, Page 19-24

A collection of Enterococci  spp. (about 96 isolates) were isolated from two Iranian raw milk cheeses, namely Lighvan and Koozeh, and subsequently, identified as Enterococcus faecium, Enterococcus faecalis, Enterococcus durans, Enterococcus casseliflavus and Enterococcus italicus by 16S rDNA sequencing. All of the 96 isolates were subjected to Agar-spot and well-diffusion assay in order to detect their ability to produce anti-microbial compounds. According to Agar-spot method, 48 out of the 96 isolates produced clear-zone on the plates against indicator organisms. With Well-Diffusion Assay, the positive isolates with clear zone decreased to 20 isolates. These 20 isolates (strains) were then subjected to rep-PCR for typing, and 15 distinct rep-PCR profiles (patterns) were identified. From these 15 positive strains, 11 strains were found to belong to Enterococcus  faecium

The Effect of Homogenization Pressure and Stages on the Amounts of Lactic and Acetic Acids of Probiotic Yoghurt

R Massoud, V Fadaei, K Khosravi-Darani

Applied Food Biotechnology, Vol. 2 No. 1 (2015), 19 February 2015, Page 25-29

Nowadays the use of probiotic products especially yogurt, due to having wonderful and health properties, has become popular in the world. In this study, the effect of homogenization pressure (100, 150 and 200 bars) and stage (single and two) on the amount of lactic and acetic acids was investigated. Yoghurts were manufactured from low-fat milk treated using high pressure homogenization at 100,150 and 200 bar and at 60°C. The amount of lactic and acetic acids was determined after the days 1, 7, 14 and 21 of storage at 4ºC. The experiments were set up using a completely randomized design. With the increase of pressure and stage of homogenization, the amount of both acids was increased (p<0.01). The greatest amount of lactic and acetic acids during the storage period was observed in the sample homogenized at a pressure of 200 bars and two stages.

The modern lifestyle is characterized by a continuous increase in the demand of ready-to-eat fresh food products subjected to minimal processes prior marketing. Attention is drawn towards the effect of this processing on the antioxidant/antiradical properties of two typical Italian salads belonging to Cichorium genus. Four chemical assays (anti-peroxyl radical activity, DPPH• assay, metal chelating ability assay, and reducing power assay) were used for evaluating these properties. The results indicated that the anti-peroxyl radical activity, the anti-DPPH radical activity, the metal chelating ability, and the reducing power were significantly higher in fresh samples as compared to 8-days stored samples (p<0.001). Minimal processing applied to vegetables further affected the tested properties causing a decrease over time from 24h to 8d of storage at 4°C. Overall, the results presented in this study showed that any minimal processing applied to ready-to-eat vegetable affects the antioxidant/antiradical properties determining a decrease in the values registered in the four chemical assays.

Evaluation of Carotenoids and Chlorophyll as Natural Resources for Food in Spirulina Microalgae

M Ghaeni, L Roomiani, Y Moradi

Applied Food Biotechnology, Vol. 2 No. 1 (2015), 19 February 2015, Page 39-44

Microalgae can produce various natural products such as pigments, enzymes, unique fatty acids and vitamins that benefit humans. The objective of the study was evaluation of carotenoids (beta carotene, zeathanthin, lutein, lycopene and astaxanthin) and chlorophyll a in spirulina microalgae. Spirulina powder has been produced by Jordan’s method in Iran. Carotenoids were extracted from Spirulina platensis by adopting a method described by Reboul; then the sample was prepared and injected into a HPLC instrument with triplicate injection. Chlorophyll`s biomass content was determined by spectrophotometer. After assaying the curves of HPLC, the amount of chlorophyll a, astaxanthin, beta carotene, lycopene, zeaxanthin and lutein in spirulina was determined as 4.3±0.14, 0.21±0.02, 7393±2.76, 741±2.32, 6652±3.69 and 424±2.83 μg/ml respectively. Beta carotene account for 80% of the carotenoids present in spirulina after that zeaxanthin was most. At last, Spirulina was a good source for carotenoids as a pro-vitamin A in organisms.

Using titanium dioxide nano-silver packaging, which is antibacterial and resistance to the diffusion of gases such as oxygen, is increasing in food industry. Therefore, we compared the effect of titanium dioxide-based nano-silver packaging and conventional polyethylene packaging on the fungal flora of consuming bread in order to increase the shelf-life storage of consuming bread. One hundred forty four samples of 6 different types of loaf of bread were randomly obtained from 12 bakeries in District 2 of Tehran. The samples were packaged with 3%, 5% and 10% nano-coatings, and also conventional polyethylene coatings as the control group. The bacterial examination and monitoring of samples, according to the national standards of Iran, was carried out 3 times, on the days 1, 3, 7, 14 and 28 of the study period. This study showed that the film type and storage period were the main factors, which significantly influenced the fungal flora of bread. The lowest rate of various fungi growth (%14) was observed in the 10% nano-film, while the highest rate of various fungi growth (47%) was observed in the conventional polyethylene coating (P<0.001). With the increase of the storage period, the number of various fungi increased; however, this correlation was not similar in most of the breads and fungi types, and there were significant difference between them in this regard (P=0.001). According to the results of the present study, due to increasing population growth and in order to improve food security, the use of packages with nano-silver particles, which are based on titanium dioxide, prevails over the polyethylene packages. Therefore, using such packages is highly recommended in the bakery industry.

Short Communication

This study aims to determine the effect of fermentation condition and Saccharomyces strains on the pH, foam property and CO2 concentration of non-alcoholic beer (Ma-al-shaeer). For this, the beer samples were inoculated with four different species of Saccharomyces (Saccharomyces rouxii 70531, S. rouxii 70535, S. ludwigii 3447 and S. cerevisiae 70424) and fermented for 48h in both aerobic and periodic aeration at three different temperatures. Then their pH, CO2 concentration and foam property were analyzed in 12h intervals during 48h fermentation. The results shows that the treatments with 4×107 and periodic aeration at 24˚C showed the greatest decrease in pH, and the treatments with 107 and aerobic-periodic aeration at 4˚C showed the lowest decrease in pH. The highest and lowest amounts of CO2 and foam property were obtained in the treatments with 4×107 inoculation, aerobic condition, and the treatments with 107, periodic aeration, respectively. These results further demonstrated that the highest drop in pH, and the highest ability of producing CO2 and foam were for S. cerevisiae 70424, and the lowest belonged to S. rouxii 70531. The overall outcome of the study points to the fact that physico-chemical properties of Ma-al-shaeer is important from the consumers' point of view. Therefore, S. cerevisiae with 4×107 inoculation and aerobic condition at 4˚C has promising potential for producing Ma-al-shaeer with good physicochemical properties.