Review Article

Bio-processing of Agro-industrial Wastes for Production of Food-grade Enzymes: Progress and Prospects

Parmjit S Panesar, Rupinder Kaur, Gisha Singla, Rajender S Sangwan

Applied Food Biotechnology, Vol. 3 No. 4 (2016), 1 October 2016, Page 208-227

Background and Objectives: In the era of global industrialization, enzymes are being used extensively in the various sectors including food processing. Owing to the high price of enzymes, various initiatives have been undertaken by the R&D sector for the development of new processes or improvement in the existing processes for production of cost effective enzymes. With the advancement in the field of biotechnology, different bioprocesses are being used for utilization of different agro-industrial residues for the production of various enzymes. This review focuses on different types of agro-industrial wastes and their utilization in the production of enzymes. The present scenario as well as the future scope of utilization of enzymes in the food industry has also been discussed.

Results and Conclusion: The regulations from the various governmental as well as environmental agencies for the demand of cleaner environment have led to the advancement in various technologies for utilization of the wastes for the production of value-added products such as enzymes. Among the different types of fermentation, maximum work has been carried under solid state conditions by batch fermentation. The research has indicated the significant potential of agro-industrial wastes for production of food-grade enzymes in order to improve the economics of the process.

Conflict of interests: The authors declare no conflict of interest.

Biotechnology: Two Decades of Experimentation with Genetically Modified Foods

Marjan Ajami, Mohammad Alimoradi, Mohammad Ali Ardekani

Applied Food Biotechnology, Vol. 3 No. 4 (2016), 1 October 2016, Page 228-235

Background and Objective: Over the recent years, genetically modified food in varieties of corn, soybeans, canola and cotton have been introduced to the global market. This study reviews the health and nutritional value of genetically modified foods in the past two decades.

Results and Conclusions: Contrary to the present biotechnological claims, transgenic products did not prove to be so flawless, and actually failed to maintain social satisfaction. Genetically modified foods could not gain an increase in the yield potential. Planting natural products and genetically modified products in parallel lines will absolutely result in genetic infection from the side of genetically modified foods. One of the major anxieties of the anti- genetically modified foods activism is the claim that genetically modified crops would alter the consumable parts of the plant quality and safety. Genetically modified foods have shown to have inadequate efficiency and potential adverse effects in both fields of health and biodiversity. This review has presented studies of genetically modified foods performances in the past two decades, and concludes that the wide application and the over generalization of genetically modified foods are not fundamentally recommended.

Conflict of interest: Authors declare that there is no conflict of interest.

Original Article

Optimization of Protease Production by Psychrotrophic Rheinheimera sp. with Response Surface Methodology

Mrayam Mahjoubin-Tehran, Bahar Shahnavaz, Razie Ghazi-Birjandi, Mansour Mashreghi, Jamshid Fooladi

Applied Food Biotechnology, Vol. 3 No. 4 (2016), 1 October 2016, Page 236-245

Background and Objectives: Psychrotrophic bacteria can produce enzymes at low temperatures; this provides a wide biotechnological potential, and offers numerous economical advantages over the use of mesophilic bacteria. In this study, extracellular protease production by psychrotrophic Rheinheimera sp. (KM459533) was optimized by the response surface methodology.

Materials and Methods: The culture medium was tryptic soy broth containing 1% (w v -1 ) skim milk. First, the effects of variables were independently evaluated on the microbial growth and protease production by one-factor-at-a-time method within the following ranges: incubation time 24-120 h, temperature 15-37°C, pH 6- 11, skim milk concentration 0-2% (w v -1 ), and inoculum size 0.5-3% (v v -1 ). The combinational effects of the four major variable including temperature, pH, skim milk concentration, and inoculum size were then evaluated within 96 h using response surface methodology through 27 experiments.

Results and Conclusion: In one-factor-at-a-time method, high cell density was detected at 72h, 20°C, pH 7, skim milk 2% (w v -1 ), and inoculum size 3% (v v -1 ), and maximum enzyme production (533.74 Uml-1 ) was achieved at 96h, 20°C, pH 9, skim milk 1% (w v -1 ), and inoculum size 3% (v v -1 ). The response surface methodology study showed that pH is the most effective factor in enzyme production, and among the other variables, only temperature had significant interaction with pH and inoculum size. The determination coefficient (R2 =0.9544) and non-significant lack of fit demonstrated correlation between the experimental and predicted values. The optimal conditions predicted by the response surface methodology for protease production were defined as: 22C, pH 8.5, skim milk 1.1% (w v -1 ), and inoculum size 4% (v v -1 ). Protease production under these conditions reached to 567.19 Uml-1 . The use of response surface methodology in this study increased protease production by eight times as compared to the observed before optimization.

Conflict of interests: The authors declare no conflict of interest.

Antioxidant, Antibacterial and Color Analysis of Garlic Fermented in Kombucha and Red Grape Vinegar

Ali Ebrahimi Pure, Monir Ebrahimi Pure

Applied Food Biotechnology, Vol. 3 No. 4 (2016), 1 October 2016, Page 246-252

Background and Objective: Garlic, in different types, is a very common food ingredient all over the world. Traditionally, garlic is fermented in grape vinegar to produce garlic pickles; in this study, to produce a novel fermented food, garlic was fermented in kombucha beverage; then, antibacterial and chemical properties and color changes of garlics fermented in kombucha and vinegar were compared with each other and those of fresh garlic.

Material and Methods: Folin-Ciocalteu assay was performed to evaluate total phenolic contents; free radical scavenging activity was evaluated using 2,2- diphenyl-1-picrylhydrazyl. Disk diffusion method was performed to measure inhibitory activity against testing bacteria. A digital method was designed for color analysis. All data were statistically analyzed by ANOVA test at significant level of (p≤0.05).

Results and Conclusion: Fresh garlic extract had the highest inhibitory effect (mean 27.7 mm) against tested bacteria; kombucha fermented garlic showed bigger inhibition zone (mean 21.7 mm) than vinegar fermented garlic (mean 17.9 mm). Anti-staphylococcus aureus activity of fresh garlic was stronger than gentamycin and amoxicillin; inhibitory effect of garlic extracts against tested bacteria was significant in comparison with standard antibiotics. Fresh-garlic extract contained highest amount of phenolic contents; fermentation of garlic in kombucha decreased phenolic content of garlic bulbs by 1.92% and IC50 factor for antioxidant activity was 10.25% higher than fresh garlic; fermentation in vinegar reduced 21% of phenolic contents and IC50 obtained 47.4% higher than fresh garlic. Fermentation of garlic reduces the density of colors and luminosity, but the reduction in garlics fermented in vinegar is more than in kombucha. Appearance of vinegar fermented garlic changed to yellowish and kombucha inclined the color to reddish. Fermentation of garlic in kombucha provides better preservation of biological properties of garlic than in grape vinegar.

Conflict of interests: We declare that we have no conflicts of interests.

Comparison of Antioxidant and Antibacterial Activities of Free and Encapsulated Garlic Oil with Beta-cyclodextrin

Khadijeh Khoshtinat, Mohsen Barzegar, Mohammad Ali Sahari, Zohreh Hamidi

Applied Food Biotechnology, Vol. 3 No. 4 (2016), 1 October 2016, Page 254-268

Background and Objectives: Application of garlic oil in food industry can be improved by encapsulation. There is no study about the formation of inclusion complex of garlic oil by beta-cyclodextrin. The aim of the present study is comparison of the antioxidant and antibacterial activities of free and encapsulated garlic oil with beta-cyclodextrin.

Materials and Methods: Antioxidant activity was determined by 1, 1- diphenyl-2- picryl-hydrazyl assay, and antibacterial properties by agar well diffusion, minimum inhibitory concentration, minimum bactericidal concentration and bacterial growth assay. Statistical analysis was performed by Minitab statistical software.

Results and conclusion: Garlic oil had poor antioxidant activity (EC50, 5222 µg ml-1 ) and EC50 because garlic oil/beta-cyclodextrin (containing 1495 µg ml-1 released garlic oil) was achieved after 5 h and 25 min. Agar well diffusion showed no inhibition zone on Muller Hinton Agar for garlic oil and garlic oil/betacyclodextrin (with initial release (shaking at 150 rpm for 24 h at 37ºC) and without initial release). Staphylococcus aureus was the most susceptible bacterium to garlic oil, and garlic oil/beta-cyclodextrin with and without initial release (minimum inhibitory concentration 10-5 , 10-4 and 10-3 % w v -1 , respectively); however, Bacillus cereus was the most resistant. The effect of initial release for garlic oil/betacyclodextrin on inhibiting the growth of all four bacteria was significant. There was no significant difference (P>0.05) between the inhibitory effect of garlic oil and garlic oil/beta-cyclodextrin with initial release on Staphylococcus aureus and Bacillus cereus, also Salmonella entrica and Escherichia coli. Garlic oil showed a weak antioxidant activity in 1, 1- diphenyl-2-picryl-hydrazyl assay. Garlic oil and its complex were not able to penetrate to the solid media; therefore, no inhibition zone and no antibacterial activity in the agar well diffusion assay were observed. Initial release of garlic oil/beta-cyclodextrin had significant impact on the inhibition of four bacterial growth, similar to free garlic oil. Since encapsulation of garlic oil can cover its drawbacks (low solubility in water, liquid form, and intense odor), garlic oil/beta-cyclodextrin could be considered as an nonsynthetic antibacterial agent.

Conflict of interests: The authors declare no conflict of interest.

Isolation and Identification of Alicyclobacillus with High Dipicolinic Acid and Heat Resistant Proteins from Mango Juice

Hamid Reza Akhbariyoon, Maryam Mirbagheri, Giti Emtiazi

Applied Food Biotechnology, Vol. 3 No. 4 (2016), 1 October 2016, Page 270-274

Background and Objectives: Microbial spoilage of juices and industries related with Alicyclobacillus are considerable international issues. This spore-forming bacterium causes changes in juices odor and taste. The isolation and identification of Alicyclobacillus contamination in juice producing and packaging industries has an essential role in the prevention and control of this type of spoilage bacterium in HACCP (Hazard analysis and critical control points ) manner.

Materials and Methods: A thermo-acidophilic, non-pathogenic and sporeforming bacterium was isolated from mango juice. Preliminary identification of the isolates was based on morphological, biochemical and physiological properties. Identification at species level was made by PCR amplification. The influence of temperature in the range of 25-65°C in the growth of bacterium and in the range of 80-120°C in spore-resistant and heat resistant proteins was investigated and compared with other spore producing bacteria.

Results and Conclusion: Phylogenetic analysis of the 16S rRNA gene sequencing indicated that the isolated strain constituted a distinct lineage in the Alicyclobacillus cluster and submitted to NCBI with access number Alicyclobacillus HRM-5 KM983424.1. The spores resisted 110°C for 3 h, and produced 28% dipicolinic acid more comparable to Bacillus licheniformis. Also they could produce 0.69 mg heat resistance protein after 1.5 h treatment in 100°C. The results showed that this strain could have biotechnological applications.

Conflict of interests: The authors declare no conflict of interest.

Characterization of Probiotic Fermented Milk Prepared by Different Inoculation Size of Mesophilic and Thermophilic Lactic Acid Bacteria

Sara Nasiri Boosjin, Vajiheh Fadaei Noghani, Mahnaz Hashemiravan

Applied Food Biotechnology, Vol. 3 No. 4 (2016), 1 October 2016, Page 276-282

Background and Objectives: Importance of development of novel probiotic fermented milk and challenge made for its acceptability is well known. In this research, the impact of different inoculation sizes of yogurt and DL-type starter culture (mesophilic and thermophilic LAB) on titratable acidity, viscosity, sensorial and microbial properties of fermented milk was investigated; and finally, probiotic Langfil was produced.
Materials and Methods: Fermented milk produced by 1, 2 and 3% v v-1 inocula consisting thermophilic: mesophilic starter cultures 10:90 (Lactococcus lactis subsp. lactis, Lactococcus lactis subsp. cremoris, Lactococcus lactis subsp. lactis, Lactococcus lactis subsp. lactis biovar. diacetylactis and Leuconostoc mesenteroides subsp. cremoris. Streptococcus thermophilus and Lactobacillus delbrueckii subsp. Bulgaricus) were analyzed for determination of titratable acidity, viscosity, viability of mesophilic starter cultures and sensory properties on days 5, 10, and 15 of storage at 4°C. Then, the most suitable treatments were selected for the producing probiotic Langfil, containing probiotic starter culture (2% v v-1 inoculums with equal ratio of Lactobacillus acidophilus and Bifidobacterium bifidum. Lactococcus lactis and L. cremoris were counted on M17 agar, while Leuconostoc and Lactobacillus were counted aerobically on tomato juice agar and MRS bile agar, respectively. Bifidobacterium was cultured anaerobically on MRS bile agar. Sensory evaluation was carried out by ten trained panelists, based on a nine-point hedonic scale during the cold storage.
Results and Conclusion: According to results, the best organoleptic properties were achieved in the product prepared with 2% the mesophilic and thermophilic starter cultures and 2% probiotic. This product had a high viscosity. An Iranian probiotic Langfil with desired properties was produced using the best treatment prepared.
Conflict of interests: The authors declare no conflict of interest.