Journal of Food Quality and Hazards Control

91

Authors: -

-

93-98

Authors: Y. Shahbazi

Background: There is growing demand to improve physicochemical, microbiological, and sensory properties of fresh foods using natural herbal antimicrobial and antioxidant compounds. The aim of the present study was to investigate antioxidant and antibacterial properties of some native edible plants of Kermanshah, Western Iran. Methods: The methanolic extracts of leaves of Falcaria vulgaris, Allium rotundum, Tragopogon graminifolius, and Mentha longifolia plants were prepared. The antibacterial effects of these four plant extracts were determined on Salmonella typhimurium, Bacillus subtilis, B. cereus, Staphylococcus aureus, Listeria monocytogenes, and Escherichia coli O157:H7 using micro-broth dilution and agar disk diffusion assays. Also, the 2, 2-diphenyl-1-picrylhydrazyl hydrate assay was used for determination of antioxidant properties of the plant extracts. The analysis was performed using SPSS 16.0 (Chicago, IL, USA) software package. Results: The most antibacterial effectiveness was significantly (p<0.05) found for M. longifolia extract. The following sequence inhibition effect on investigated bacterial strains was observed: M. longifolia>T. graminifolius>A. rotundum>F. vulgaris. Moreo-ver, Gram-negative bacteria were more resistant to the presence of methanolic plant extracts than Gram-positive bacteria. The highest antioxidant activity (based on IC50) was significantly (p<0.05) found for M. longifolia (0.88±0.12 mg/ml); as well as these rates for T. graminifolius, A. rotundum, and F. vulgaris extracts were 0.45±0.78, 0.26±0.07, and 0.14±0.23 mg/ml, respectively. Conclusion: The studied edible plants had antimicrobial and antioxidant activities that recommend as potential preservatives in food products. However, methanolic extract of M. longifolia had the best antibacterial and antioxidant properties in vitro.

103-108

Authors: R. Zarezadeh Mehrizi, Z. Emam-Djomeh, M. Shahedi, J. Keramat, K. Rezaei, E. Loni

Background: Literature review shows that there are not sufficient data about polyphenolic compounds of peel of Iranian pomegranate. So, this work was mainly undertaken to determine phenolic compounds and antioxidant activity of dried peel of Iranian pomegranate. Methods: Pomegranate fruits were obtained from mature fruits grown in Saveh, Iran and the Pomegranate Peel (PP) were dried with three different methods. Powders of PP were extracted with four different solvents, using a soxhlet apparatus. The compounds of PP extracts were analyzed by High Performance Liquid Chromatography (HPLC). Then, yield percentage and Radical Scavenging Activity (RSA) were determined. Statistical analysis was performed using the SAS 9.1 software. Results: Different ranges of tannic acids, testosterone and α-estradiol, estriol, estrone, cyanidin 3-glucoside, cyanidin3,5-diglucoside, pelargonidin 3-glucoside, pelargonidin 3,5diglucoside, and delphinidin 3-glucoside were identified. Both the highest yield percentage (18.820±0.661) as well as the highest RSA percentage (63.862±0.376) were obtained from the ethanol showing significant (p<0.05) difference with the other solvents. Drying method of PP showed no significant (p>0.05) relationship with yield of extraction and also antioxidant activity of the PP extracts. Conclusion: HPLC analysis identified some various phenolic compounds in Iranian PP extract showing considerable antioxidant activities. Although drying method showed no relation with yield of extraction and also antioxidant activity of the PP extracts, but type of solvent was effective on yield of extraction and type of extracted compounds of PP.

113-118

Authors: M. Ghorbani, S.S. Saei-Dehkordi, A. Mohebbi, A. Pak

Background: Iran could be considered as one of the most important producers of honey all over the world. This investigation was conducted to evaluate some chemical quality characteristics of honey produced in Iran. Methods: Totally, natural (n=80) and commercial (n=20) honey samples were randomly collected from North-West and South-West regions of Iran. Hydroxymethylfurfural (HMF) levels, phenolic contents, antiradical activity, and antioxidative potency of the samples were analyzed. Data were statistically analyzed using SPSS version 16. Results: The HMF level in 4 out of 80 (5%) natural honey samples and 14 out of 20 (70%) of commercial honey samples was higher than the recommended safety limit set by the Iran national standard. The average phenolic content was significantly (p<0.05) lower for commercial honeys (20.51 mg of Gallic Acid Equivalents (GAE)/100 g of honey) than for natural honeys (55.37 mg of GAE/100 g of honey). The mean IC50 of natural honey samples was 40.63 mg/ml with a range of 14.2-84.1 mg/ml; however, the mean IC50 of commercial honey samples was 341.96 mg/ml, with a range of 115-997.4 mg/ml. The difference between mean values of β-carotene bleaching inhibition of natural honey (54.54 mg/ml) and commercial ones (25.37 mg/ml) was found to be statistically signifi-cant (p<0.05). Also, there was a significant (p<0.05) difference between chemical quality characteristics of honeys between two geographical regions. Conclusion: In conclusion, HMF levels, phenolic contents, antiradical activity, and antioxidative potency of Iranian natural honeys were remarkably more acceptable and suitable than commercial honeys produced in the country.