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Abstract: The effect of hen egg white lysozyme (HEWL) and bacteriophage lambda lysozyme (LaL) in combination with high pressure (HP) treatment on the inactivation of four gram-negative bacteria (Escherichia coli O157:H7, Shigella flexneri, Yersinia enterocolitica and Salmonella typhimurium), was studied in skim milk (pH 6.8; a w 0.997) and in banana juice (pH 3.8; a w 0.971). In the absence of lysozymes, S. flexneri was more sensitive to HP in milk than in banana juice, while the opposite was observed for the other three bacteria. In combination with HP treatment, LaL was more effective than HEWL on all bacteria in both milk and banana juice. Depending on the bacteria, inactivation levels in banana juice were increased from 0.4–2.7 log units by HP treatment alone to 3.6–6.5 log units in the presence of 224 U/ml LaL. Bacterial inactivation in milk was also enhanced by LaL but only by 0.5–2.1 log units. Under the experimental conditions used, LaL was more effective in banana juice than in milk, while the effectiveness of HEWL under the same conditions was not significantly affected by the food matrix. This effect could be ascribed to the low pH of the banana juice since LaL was also more effective on E. coli in buffer at pH 3.8 than at pH 6.8. Since neither LaL nor HEWL are enzymatically active at pH 3.8, we analysed bacterial lysis after HP treatment in the presence of these enzymes, and found that inactivation proceeds through a non-lytic mechanism at pH 3.8 and a lytic mechanism at pH 6.8. Based on these results, LaL may offer interesting perspectives for use as an extra hurdle in high pressure food preservation. [Copyright &y& Elsevier]

Abstract: The antibacterial working range of six lysozymes was tested under ambient and high pressure, on a panel of five gram-positive (Enterococcus faecalis, Bacillus subtilis, Listeria innocua, Staphylococcus aureus and Micrococcus lysodeikticus) and five gram-negative bacteria (Yersinia enterocolitica, Shigella flexneri, Escherichia coli O157:H7, Pseudomonas aeruginosa and Salmonella typhimurium). The lysozymes included two that are commercially available (hen egg white lysozyme or HEWL, and mutanolysin from Streptomyces globisporus or M1L), and four that were chromatographically purified (bacteriophage λ lysozyme or LaL, bacteriophage T4 lysozyme or T4L, goose egg white lysozyme or GEWL, and cauliflower lysozyme or CFL). T4L, LaL and GEWL were highly pure as evaluated by silver staining of SDS-PAGE gels and zymogram analysis while CFL was only partially pure. At ambient pressure each gram-positive test organism displayed a specific pattern of sensitivity to the six lysozymes, but none of the gram-negative bacteria was sensitive to any of the lysozymes. High pressure treatment (130–300 MPa, 25 °C, 15 min) sensitised several gram-positive and gram-negative bacteria for one or more lysozymes. M. lysodeikticus and P. aeruginosa became sensitive to all lysozymes under high pressure, S. typhimurium remained completely insensitive to all lysozymes, and the other bacteria showed sensitisation to some of the lysozymes. The possible applications of the different lysozymes as biopreservatives, and the possible reasons for the observed differences in bactericidal specificity are discussed. [Copyright &y& Elsevier]

• Heat processing doesn't affect R. differens ' proximate, amino & fatty acids' content. • Boiling & further roasting (165 °C, 45 min) increases its' Ca, Cu, Fe, Mn & Zn content. • Boiling (100 °C, 30 min) reduces R. differens' vitamin B12 content by 70–85%. • Heat processing increases the color uniformity between brown and green polymorphs. • Lipid oxidation is majorly responsible for heat-processed R. differens ' aroma & color. Heat processing is commonly used to prepare edible insects for consumption. This study aimed at determining the effect of boiling and subsequent oven roasting on Ruspolia differens ' nutrient composition, colour and odor compounds. Boiling leads to: a significant increase in protein and decrease in fat content on a dry matter basis; a minimal influence on its amino and fatty acids profile; a significant reduction in its ash content due to leaching of phosphorus, potassium and sodium; a significant increase in iron, zinc, copper, manganese and calcium content; and a fivefold reduction in the amount of vitamin B12. Roasting leads to a relative increase in the amount of calcium and trace mineral elements but doesn't affect other nutrients. Roasting results into a more uniform colour intensity when green and brown polymorphs are roasted together. Lipid oxidation is responsible for the colour and aroma of heat processed R. differens. [ABSTRACT FROM AUTHOR]

• Larval yields were significantly higher for substrates with C/N ratio of 15. • Larval nutrients accumulation was highest in substrates with C/N ratio of 15. • Compost maturity time was shortened to five weeks. • Nitrogen and phosphorus retention were highest in the substrate with C/N ratio of 15. Efforts to recycle organic waste using black soldier fly (BSF) larvae into high-quality alternative protein ingredients in animal feeds and organic fertilizers have gained momentum worldwide. However, there is limited information on waste manipulation to increase nutrient retention for enhanced larval performance and frass fertilizer quality. In the present study, brewer's spent grain with a carbon to nitrogen (C/N) ratio of 11 (control) was amended with sawdust to obtain substrates with C/N ratios of 15, 20, 25 and 30. The effects of substrate C/N ratios on BSF larval yield, waste degradation, biomass conversion efficiency, compost maturity and nutrient levels of frass fertilizer were evaluated. Substrates amended with sawdust did not significantly affect waste degradation efficiency and biomass conversion rates of BSF larvae. The wet and dried larval yields were significantly higher for substrates with C/N ratio of 15 compared to the other amended substrates. An amended substrate with C/N ratio of 15 enhanced nutrients uptake by BSF larvae, and increased nitrogen (N) and phosphorus retention in frass compost by 21 and 15%, respectively. Compost maturation time was shortened to five weeks, as indicated by the stable C/N ratios and high seed germination indices. This study has demonstrated that the amendment of the substrate with sawdust to C/N ratio of 15 could generate compost with desirable nutrients for use as high-quality fertilizer for organic farming. [ABSTRACT FROM AUTHOR]

• Protein and fat make up 86–89% of the Ruspolia differens ' nutrient components. • A vital source of PUFAs, essential amino acids, & trace elements (Fe, Zn, Mn, Cu). • R. differens has a high ω-6/ω-3 ratio & tryptophan is its first limiting amino acid. • Unlike geographical area, season influences R. differens ' nutrient composition. • It can contribute to alleviating protein, Zn, Fe, & vitamin B12 deficiency. This research investigates the effect of swarming season and sourcing geographical area on the nutrient composition of R. differens. On a dry matter basis, protein (34.2–45.8%) and fat (42.2–54.3%) are the major macro-nutrients. Leucine (80. 9–88.5), lysine (54.0–69.8) and valine (59.2–61.8) are the most abundant essential amino acids (EAA) (mg/g protein). Tryptophan is the most limiting EAA. Its EAA composition is like the children and adults' reference protein. Its fat is highly unsaturated (63.5–64.7). Oleic (38.4–42.7), linoleic (19.0–23.0) and palmitic (26.6–27.8) fatty acids (FA) (g/100 g total FA) are the most abundant. Geographical area significantly influences its mineral content within seasons. Season significantly influences its fat, protein, ash and mineral content but not its AAs' and FAs' content. Both factors significantly influence its vitamin B12 content (0.73–1.35 µg/100 g). [ABSTRACT FROM AUTHOR]

[Display omitted] • Ruspolia differens Serville is consumed as healthy food in more than 20 countries worldwide. • Deep frying significantly reduces the crude protein, ash, and fibre contents of R. differens. • Blanching method increases Omega-3, Omega-6, flavonoids, and sterols levels of R. differens. • Blanched and boiled products of R. differens showed considerably high iron and zinc contents. • Implications of dietary and therapeutic compounds of R. differens on nutrition and health are discussed. Long-horned grasshopper (Ruspolia differens Serville) is a tasty delicacy in over 20 African countries. This study evaluated the impact of diverse post-harvest thermal treatment (blanching, boiling, toasting, and deep-frying) on the nutrients, total flavonoid content and sterols preservation of R. differens products. Crude protein, ash, and fibre of R. differens was drastically reduced by deep-frying technique. There was increase in Omega-3 (α -linolenic acid), Omega-6 fatty acid (linoleic and arachidonic acids) and sterols [(22 Z)-27-Norergosta-5,22-dien-3 β -ol, cholesterol, campesterol, cholest-4-ene-3-one and β -sitosterol] and flavonoids (2–3 folds) during blanching compared to other techniques. The iron and zinc content increased significantly in blanched and boiled products of R. differens. Thus, losses of nutrients, total flavonoid content and sterols during processing of R. differens for food can be mitigated by employing blanching technique, which is cheaper and least time-consuming. The implications of these dietary and therapeutic compounds on human nutrition and health are discussed. [ABSTRACT FROM AUTHOR]

Abstract: A highly efficient method was developed for the isolation and purification of the periplasmic Escherichia coli lysozyme inhibitor protein Ivy. After isolation by osmotic shock from an E. coli overexpression strain, Ivy was purified to >95% purity using a single affinity chromatography step with hen egg white lysozyme as a ligand. Further, the specificity of Ivy against various types of lysozymes (hen egg white lysozyme, c-type; mutanolysine, ch-type; cauliflower lysozyme, not further classified; goose egg white lysozyme, g-type; lambda lysozyme, λ-type and T4 lysozyme, v-type) was investigated. Most strongly inhibited was hen egg white lysozyme, followed by goose egg white lysozyme and finally T4 lysozyme, while no inhibition was observed for the other lysozymes. These results clearly indicate that Ivy is a relatively specific inhibitor of vertebrate lysozymes belonging to the c- and g-type and that its inhibition profile corresponds to the structural and evolutionary relatedness of the lysozymes. The availability of pure Ivy and the elucidation of its inhibition profile will contribute to the further identification of its biological function in bacteria. [Copyright &y& Elsevier]