Fenton Reaction Facilitates The Fungal Infection On The Unicellular Alga Haematococcus Pluvialis and Discovery of a Biosafe and Environment-Friendly Chemical That Blocks The Infection

Background The green microalga Haematococcus pluvialis is used as cell factories for producing astaxanthin, the high-value natural compound with multiple biological functions. However, H. pluvialis is prone to the infection by a parasitic fungus Paraphysoderma sedebokerense, which is the most devastating threat to the mass culture of H. pluvialis all over the world. Little is known for the mechanisms underlying the infection process, though it is of great essential for developing effective measures to mitigate the pathogen threatening for the natural astaxanthin industry. Results We observed that there were heat-stable substances with small molecular weight produced during the infection process, which significantly stimulated the parasitism process and enhanced the susceptibility of H. pluvialis cells to the pathogen. Systematic approaches including multi-omics, biochemical and imaging analysis were deployed to uncover the identity of the metabolites and the underlying mechanisms. Two metabolites, 3-hydroxyanthranilic acid and hordenine were identified and proved to stimulate the infection via driving fenton reaction mediated oxidative stress to H. pluvialis. The reaction generated hydroxyl radicals to disrupt the subcellular components of the algal cells and to make the algal cells more susceptible to the infection. Based on these findings, a biosafe and environment-friendly antioxidant butylated hydroxyanisole was selected to inhibit the fungal infection, which completely abolished the infection at 12 ppm. Conclusions This study provide for the first time, a framework to dissect the functions of secondary metabolites in the interaction between the unicellular algal H. pluvialis and its fungi parasite, indicating that oxidative degradation is a strategy used for the fungal infest. Eliminating the oxidative burst through adding antioxidant butylated hydroxyanisole could be an effective measure to reduce parasitic infection in H. pluvialis mass culture.

Combined effect of irradiation and butylated hydroxyanisole on shelf life and quality of beef at ambient temperature

The study was aimed to evaluate the effect of gamma irradiation and butylated hydroxyanisole (BHA) on meat quality traits and safety of beef. Samples were divided into four treatment groups treated with 0.01% BHA and gamma ray having T0 (Control), T1 (3 kGy), T2 (5 kGy) and T3 (7 kGy), respectively. The analyses were conducted at 0, 3, 5 and 7 days of interval. The study was conducted in completely randomized factorial (CRD) design. Traits evaluated were color value (L*, a*, b*), pH, drip loss, cooking loss, ERV and WHC, DM, moisture, CP, fat, ash, thiobarbituric acid reactive substances (TBARS), peroxide value (POV), free fatty acid (FFA), total coliform count (TCC), total viable count (TVC) and total yeast mould count (TYMC). Color, flavor, tenderness, juiciness and overall acceptability were significantly differed (p<0.01) for days of intervals. Positive and significant interaction (p<0.01) between treatment and days of interval was found for color value (L*, a*, b*), drip loss, cooking loss, ERV, WHC except raw pH. There were found positive and significant interaction (p<0.01) between treatment and days of interval for DM, CP, FFA and TBARS except POV. The TYMC and staphylococcus were significantly decreased (p<0.05) at different treatment groups compared to control group. Salmonella non-significantly (p>0.05) increased and staphylococcus significantly (p<0.01) decreased with increasing irradiated doses in beef. Hence, it may be concluded that BHA treated irradiated beef had a potential effect of shelf life to maintain quality and safety aspect of beef.

Antioxidant capacity of pitcher (Nepenthes) extract on oxidative rancidity of sun-dried squid

Consumers demand new biologically natural-active ingredients with a great capacity to promote a healthier advantage and free from toxicity. Pitcher (Nepenthes) is one of the naturally carnivorous climber herbs. Extract from Nepenthes plant contains numerous beneficial bioactivity characteristics. This research compared the impact of 0.05% pitcher extract demonstrated with 10 ppm butylated hydroxyanisole on the accumulation of acid value, peroxide value, carbonyl value and thiobarbituric acid during 12 months of storage. Results showed that there was no significant difference between 0.05% pitcher extract and 10 ppm butylated hydroxyanisole in respect of acid value, peroxide value, carbonyl value and thiobarbituric acid during preservation of the dried squid. Pitcher extract would be a promising alternative to replace synthetic antioxidants to overcome oxidative rancidity in the dried seafood.