The antagonistic activity of volatile compounds from Streptomyces alboflavus TD‐1 against Aspergillus ochraceus were investigated in this study. Conidial germination and mycelial growth of A. ochraceus were completely suppressed after exposure to 40 and 80 g/L of wheat bran cultures of S. alboflavus TD‐1. A total of 35 compounds (relative peak area [RA] >0.10) were identified from wheat bran cultures of S. alboflavus TD‐1. Five standard compounds were purchased for the antifungal activity assay: anisole, dimethyl trisulfide, β‐pinene, benzenamine and 1,5‐cyclooctadiene. Among these, dimethyl trisulfide and benzenamine showed strong inhibitory effects on the mycelial growth of A. ochraceus. In addition, conidial and hyphal morphological abnormalities were observed in treated A. ochraceus. Scanning electron microscopy (SEM) and OD‐260 nm absorption analysis demonstrated that disruption of membrane integrity may be a possible mechanism of action for volatiles from S. alboflavus TD‐1. This study indicates that volatiles of S. alboflavus TD‐1 have tremendous potential to act as a strategy for the biocontrol of postharvest diseases in food during storage.

Rhizomucor miehei is an important fungus that produces aspartic proteases suitable for cheese processing. In this study, a novel aspartic protease gene (RmproB) was cloned from R. miehei CAU432 and expressed in Aspergillus niger. The amino acid sequence of RmproB shared the highest identity of 58.2% with the saccharopepsin PEP4 from Saccharomyces cerevisiae. High protease activity of 1242.2 U/mL was obtained through high density fermentation in 5 L fermentor. RmproB showed the optimal activity at pH 2.5 and 40 °C, respectively. It was stable within pH 1.5–6.5 and up to 45 °C. RmproB exhibited broad substrate specificity and had Km values of 3.16, 5.88, 5.43, and 1.56 mg/mL for casein, hemoglobin, myoglobin, and bovine serum albumin, respectively. RmproB also showed remarkable milk-clotting activity of 3894.1 SU/mg and identified the cleavage of Lys21-Ile22, Leu32-Ser33, Lys63-Pro64, Leu79-Ser80, Phe105-Met106, and Asp148-Ser149 bonds in κ-casein. Moreover, duck hemoglobin was hydrolyzed by RmproB to prepare angiotensin-I-converting enzyme (ACE) inhibitory peptides with high ACE-inhibitory activity (IC50 of 0.195 mg/mL). The duck hemoglobin peptides were further produced at kilo-scale with a yield of 62.5%. High-level expression and favorable biochemical characterization of RmproB make it a promising candidate for cheese processing and production of ACE-inhibitory peptides.

Introduction Dill Anethum graveolens L. , an important member of the Umbelliferae family native to southwest Asia or southeast Europe, is widely used for flavoring foods and beverages, and for the treatment of many pathological conditions such as diseases of the uterus, cervical ectropion, flatulence, indigestion, stomachache, colic, and gas in the intestinal tract 1 3. Dill has been also reported to possess antibacterial property 4 which is believed to be the reason widely used in cans for sour cucumber and other food processes. Dill is also known for its antihyperlipidemic, and antihypercholesterolemic properties 5. As a traditional medicinal vegetable, dill increases milk production and promotes menstruation 2. However, the significant medicinal activity of dill is mainly related to its antioxidant power 6

No abstract

No abstract