Local food production can be seen worldwide, and there are several local wisdoms on food production. There are many problems on local food production, including the problem of microbiological contamination, which is considered a great concern. The safety consideration is required. In the tropical world, the problem of local tropical food production should be specially discussed. There are many cases of problematic microbiological contamination, and the quality management is still the issue for further development. A safe and acceptable approach to increase the safety and shelf life of tropical foods is the use of essential oils.

The use of bacteriocins, mainly nisin, is one of the most significant preservation technologies in the food industry. Nisin encapsulation can improve stability and homogenous distribution in food matrices. In this study, liposomes of four various lipids (lipoid S 100, lipoid S PC-3, lipoid S PC, and lipoid PC (DPPC)) were prepared by dehydration-rehydration method, and compared for entrapment efficiency, and lipid with the highest entrapment efficiency (DPPC) was characterized. The inhibitory effects of encapsulated (DPPC nanoliposomes) and free nisin on the spoilage of pasteurized milk were also studied. All experiments were performed in triplicate. Entrapment efficiency ranged from 14% (lipoid S 100) to 49% (DPPC). DPPC nanoliposomes were large unilamellar vesicles (LUV), and had an asymmetric oval shape (elliptical) with a mean diameter of 136 nm. It was revealed that pasteurized milk spoilage was delayed by both free and encapsulated nisin, but free nisin (with 38 days) was significantly more efficient in comparison with encapsulated nisin (14 days).

Withania somnifera (L.) Dunal is an erect evergreen shrub commonly known as Ashwagandha. It is widely used in Ayurvedic, and in the traditional pharmacopeia system of India. It is one of the major ingredients in many formulations prescribed for a variety of musculo-skeletal conditions including arthritis and rheumatism. In the present study, variations in the quality and quantity of proteins and antioxidant enzymes were evaluated biochemically and enzymatically from the static and suspension cultures of Withania somnifera L. The nodal segments provided the maximum callusing of 90.25±0.06% with (1mg/l) BAP and (2mg/l) Kn of 2, 4-D. The static and suspension cultures were taken for the analysis of total soluble protein, and screened for antioxidant enzyme activity [catalase (CAT), superoxide dismutase (SOD) and guaiacol peroxidase (GPX)]. The protein content (1.2016 μg/μl) was found to be higher in static culture samples (0.870 μg/μl) than the protein obtained from the suspension culture. The antioxidant enzyme activity (CAT, SOD and GPX) was higher in the static culture samples (301.01± 0.42, 198.92 ± 0.29, 103.75 ± 0.11 nkat/mg of protein) than in the suspension culture. Specific activity staining of isoenzyme pattern exhibited three isoforms (CAT 1, CAT 2 and CAT 3) in the static culture samples but CAT 1 was absent in the samples extracted from the suspension cultures. In case of SOD, four bands (SOD 1, SOD 2, SOD 3 and SOD 4) were found in both samples whereas the intensity of GPX activity was found to be more in the static culture; however, both samples exhibited three isoforms (GPX 1, GPX 2 and GPX 3). Supplementation of the required nutrients along with phytohormones under in vitro conditions might be an enhancing factor to yield antioxidant enzymes in the static culture samples.

Among the ways of pigment production, microbial synthesis has gained more interest for high growth rate, easy extraction and high yield. Pigments are used in the food industry as natural colorants and preservatives; they also have pharmaceutical applications. In this study, fungus Monascus purpureus PTCC 5303 was used to produce red, orange and yellow pigments. At first, significant variables were screened based on Plackett-Burman’s design. The optimized value of two effective factors, i.e. concentration of yeast extract and K2HPO4 by three-level, was more studied by the response surface method (RSM). The most suitable level was 2.75 g/L for yeast extract and 1.5 g/L for K2HPO4. Antimicrobial activity of the pigments was shown on Gram-positive food-borne bacteria under optimal conditions. Moreover, pigment production at optimal conditions in a bioreactor was evaluated, and the rate of production of red, orange and yellow pigments was obtained to be 2.05, 1.55 and 0.78 (ODU/ml), respectively.

Polyphenol oxidase (EC. 1.10.3.1 PPO), an ionically unbound and thermostable enzyme, was extracted from the leaves of Cinnamomum tamala having aroma flavor used to add in Indian food and vegetables as a part of spices to enhance the taste of recipes. The enzyme was purified 2.63-fold with a total yield of 9.5% by ammonium sulfate precipitation followed by Sephadex G-100 gel filtration chromatography. The purified enzyme exhibited a clear single band on sodium dodecyl sulfate (SDS) PAGE. It was found to be monomeric protein with molecular mass of about 25 kD. The zymographic study using crude extract as enzyme source showed a very clear band around 25 kD. The enzyme was optimally active at pH 7.0 and 50oC. It was active in a wide range of pH (3-9) and temperature (30–90oC). From the thermal inactivation studies in the range 60-80oC, the half-life (t1/2) values of the enzyme varied from 19 to 72 min. The inactivation energy (Ea) value of PPO was estimated to be 94.5 kJ mol-1; it showed higher specificity with substrate catechol (Km=6.8mM). Among the metal ions and reagents tested, Cu2+ (indicating its role as cofactors), Fe2+, Hg2+, protocatechuic acid, and ferrulic acid enhanced the enzyme activity, while K+, Mg2+, Co2+, kojic acid, L-ascorbic acid, ethylenediamine tetraacetic acid (EDTA), urea, sodium azide, β-mercaptoethanol, and L-cysteine inhibited its activity.

Identification and use of more efficient enzymes in the food and pharmaceutical industries is the focus of many researchers. The aim of this study was to search for a new bacterial strain capable of producing high levels of pullulanase applicable to biotechnology, the starch bioprocessing and food industries. A new pullulan hydrolyzing Bacillus strain was isolated and designated SDK2. Morphological and biochemical tests identified the strain as a putative Bacillus cereus strain, which was further characterized and confirmed through 16s rRNA sequencing, and was submitted to GeneBank, under the accession number FR6864500. Quantitative analysis of the strain’s pullulanase activity was carried out by the Dintrosalicyclic (DNS) acid-based assay. Thin layer chromatography (TLC) of the culture supernatant, identified the extracellular pullulanase as neopullulanase. Effects of temperature and pH on pullulanase activity were also studied. The optimum conditions for enzyme activity, as represented by 60°C and a pH of 7, resulted in an activity of 13.43 U/ml, which is much higher than some of the previously reported activities. However, growth of B. cereus SDK2 was also observed at a pH range of 5 to 10, and temperatures of 30°C to 50°C. The effect of metal ions and reagents, such as Mg+2, Ca+2, Zn+2, Cu+2, Fe+2, Ni+2 on enzyme activity showed that Ca+2 ions increased pullulan activity, whereas the other ions and reagents inhibited pullulanase activity. The ability of B. cereus SDK2 to produce high levels of neopullulanase stable at 60°C that can generate panose from pullulan, make this newly isolated strain a valuable source of debranching enzyme for biotechnology, the starch bioprocess and medical industries.

In the present study lactic acid production was enhanced by optimizing the three process variables viz; inoculum size, temperature and pH using three factor five level CCRD (central composite rotatable design) by Lactobacillus delbruckii under SMF (submerged fermentation process). Paneer (dairy by-product) whey was used as sole substrate for lactic acid production. Design Expert 8.0.2.0 software depicted that an optimum concentration of 8% (v/v) size of inoculum, 5.50 pH and 36.53C temperature gave lactic acid and biomass yield of 5.61 g/L and 4.27 g/L, respectively. Lactic acid production was scale up in 7.5 L bioreactor under optimized conditions and it gave lactic acid and biomass yield of 39.2±1.4 and 47.6±0.8 g/L, respectively. μg, YP/S, YP/X and productivity were found to be 0.14 h-1, 0.66 g/g, 0.7 g/g and 1.98 g/L. h, respectively. Leudking Piret equation deduced that lactic acid production was growth associated which varies from earlier reports. Lactic acid was characterized by FTIR (Fourier transform infrared spectroscopy) and HPLC (High performance liquid chromatography).