The stems of Opuntia ficus-indica known as cladodes are rich source of bioactive and functional substances, which make them important candidate for the production of health-promoting food. Cladodes powder was incorporated at different levels of substitution (2.5%, 5% and 7.5%) in cookies (butter/wheat flour: 55/100 m/m). Substitution of wheat flour by cladodes powder improved dietary fiber, ash, potassium, magnesium and calcium contents of enriched cookies. The results also revealed that cladodes supplementation increased hardness; however, it decreased a* and b* values and reduced exudate loss of cookies during storage. Moreover, rising levels of cladodes powder contribute to the increase of antioxidant activity of cookies and decreased their oxidative degradation. Sensory evaluation showed that cladodes supplementation at 5% level remained acceptable at 5-point hedonic scale. The present study suggested that cladodes supplementation in high-fat cookies not only added nutritional value to food, but also improved its functional characteristics.

A protease-producing bacterium was isolated from an alkaline wastewater of the soap industry and identified as Vibrio metschnikovii J1 on the basis of the 16S rRNA gene sequencing and biochemical properties. The strain was found to over-produce proteases when it was grown at 30 degrees C in media containing casein as carbon source (14,000 U ml(-1)). J1 enzyme, the major protease produced by V. metschnikovii J1, was purified by a three-step procedure, with a 2.1-fold increase in specific activity and 33.3% recovery. The molecular weight of the purified protease was estimated to be 30 kDa by SDS-PAGE and gel filtration. The N-terminal amino acid sequence of the first 20 amino acids of the purified J1 protease was AQQTPYGIRMVQADQLSDVY. The enzyme was highly active over a wide range of pH from 9.0 to 12.0, with an optimum at pH 11.0. The optimum temperature for the purified enzyme was 60 degrees C. The activity of the enzyme was totally lost in the presence of PMSF, suggesting that the purified enzyme is a serine protease. The kinetic constants K (m) and K (cat) of the purified enzyme using N-succinyl-L-Ala-L-Ala-L-Pro-L-Phe-p-nitroanilide were 0.158 mM and 1.14 x 10(5) min(-1), respectively. The catalytic efficiency (K (cat) /K (m)) was 7.23 x 10(8) min(-1) M(-1). The enzyme showed extreme stability toward non-ionic surfactants and oxidizing agents. In addition, it showed high stability and compatibility with some commercial liquid and solid detergents. The aprJ1 gene, which encodes the alkaline protease from V. metschnikovii J1, was isolated, and its DNA sequence was determined. The deduced amino acid sequence of the preproenzyme differs from that of V. metschnikovii RH530 detergent-stable protease by 12 amino acids, 7 located in the propeptide and 5 in the mature enzyme.

Medium composition and culture conditions for the acid protease production byAspergillus nigerI1 were optimized by response surface methodology (RSM). A significant influence of temperature, KH2PO4, and initial pH on the protease production was evaluated by Plackett-Burman design (PBD). These factors were further optimized using Box-Behnken design and RSM. Under the proposed optimized conditions, the experimental protease production (183.13 U mL−1) closely matched the yield predicted by the statistical model (172.57 U mL−1) withR2=0.914. Compared with the initial M1 medium on which protease production was 43.13 U mL−1, a successful and significant improvement by 4.25 folds was achieved in the optimized medium containing (g/L): hulled grain of wheat (HGW) 5.0; KH2PO41.0; NaCl 0.3; MgSO4(7H2O) 0.5; CaCl2(7H2O) 0.4; ZnSO40.1; Na2HPO41.6; shrimp peptone (SP) 1.0. The pH was adjusted at 5 and the temperature at30°C. More interestingly, the optimization was accomplished using two cheap and local fermentation substrates, HGW and SP, which may result in a significant reduction in the cost of medium constituents.

Aims: Wool, a recalcitrant waste mainly composed of keratin, constituted a serious problem for the environment and was not effectively valorized. This study reported the optimization of wool-waste biodegradation by a new keratinolytic bacterium Bacillus pumilus A1. The in vitro digestibility and the antioxidant potential of wool protein hydrolysate (WPH) were also investigated. Methods and Results: The antioxidant potential of WPH was evaluated using in vitro antioxidant assays, such as 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity, reducing power and metal (Fe 2+ ) chelating activity. Cultivation on 50 g l À1 of wool for 2 days, at 45°C and at initial pH of 10, resulted in maximum production of amino acids and peptides (39Á7 g l À1 ).WPH presented a very high in vitro digestibility (97%) as compared with that of the untreated wool (3%). Conclusions:The keratin present into the wool-waste was completely solubilized. Interestingly, WPH presented an important DPPH radicalscavenging activity with an IC 50 value of 0Á14 AE 0Á01 mg ml À1 . Significance and Impact of Study: WPH would be a very useful source of protein and antioxidants in animals' diets.

Aims: To investigate the distribution of chitinase IO8 in Bacillus cereus strains, the enhancing effects of the chitinase-producing B. cereus strains on biocontrol potential by dual culture assay and in vivo assay against Botrytis cinerea and also the enhancing effects of the chiIO8 on disinfectant properties against seedborne diseases. Moreover, the application of chiIO8 treatment was also observed to improve the germinative energy. Methods and Results: The purification steps included ammonium sulfate precipitation, with columns of DEAE-Sepharose anion-exchange chromatography and Sephacryl S-400 high-resolution gel chromatography. The method gave a 5Á8-fold increase in the specific activity and had a yield of 17%. The molecular weight of the partially purified chitinase chiIO8 was found to be around 30 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The optimal pH and optimal temperature of the partially purified chitinase were pH 6Á5 and 65°C, respectively. The thermostable chitinase still retained the activity after incubation for 100 min at 65°C, and it was increased about 1Á25 times than that of the control (before heating) when the enzyme solution heated at 65°C for 60 min. The partially purified chitinase chiIO8 displays a wide inhibitory spectrum towards all phytopathogenic fungi tested. chiIO8 also exhibited effective disinfectant properties against seed-borne diseases. Conclusion: The present investigation emphasizes the potential of chitinaseproducing micro-organism as promising biocontrol agents of fungal plant pathogens with chitinous cell wall. The novel chitinase chiIO8 proved an efficient, environmentally safe and user-friendly solution. Significance and Impact of the Study: This is the first investigation devoted exclusively to analyse the distribution of chitinase in B. cereus. It infers that the chitinase produced by B. cereus might play a role in the activity of the biopesticide.

BACKGROUND: The root powder of Periploca laevigata is used for preparing soft drinks and as an aromatic in Tunisia. The infusion or decoction of its root bark has widespread use in folk medicine. The plant is used to treat digestive disorders and hypertensive effects as well as other health problems.

The purpose of this study was to evaluate the effect of rosemary essential oil (250-1000 ppm) or its leaves (0.5-2%) on the quality of turkey sausage. The addition of essential oil had no signifi cant effect on the sausage texture and colour parameters. A high rosemary leaves level resulted in an increase in sausage hardness and chewiness and a decrease in lightness (L*) with respect to the control sausage. Sensory evaluation indicated that rosemary essential oil and its leaves increased the taste and the aroma scores of turkey sausage depending on the concentration. The obtained results also showed that rosemary leaves (0.5%) were more effective than essential oil in reducing total plate counts, TBARS, K 232 , and K 270 values during chill storage, in comparison with the control product. This will contribute to reducing the use of chemical additives, which are badly perceived by consumers, while increasing the sensory properties of such products.

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