Francesco Genovese

Investigation of Factors Affecting Aerobic and Respiratory Growth in the Oxygen-Tolerant Strain Lactobacillus casei N87

Aerobic and respiratory cultivations provide benefits for some lactic acid bacteria (LAB). Growth, metabolites, enzymatic activities (lactate dehydrogenase; pyruvate and NADH oxidases, NADH peroxidase; catalase), antioxidant capability and stress tolerance of Lactobacillus casei N87 were evaluated in anaerobic, aerobic and respiratory (aerobiosis with heme and menaquinone supplementation) batch cultivations with different dissolved oxygen (DO) concentrations. The expression of pox (pyruvate oxidase) and cydABCD operon (cytochrome bd oxidase complex) was quantified by quantitative Real Time polymerase chain reaction. Respiration increased biomass production compared to anaerobiosis and unsupplemented aerobiosis, and altered the central metabolism rerouting pyruvate away from lactate accumulation. All enzymatic activities, except lactate dehydrogenase, were higher in respiratory cultures, while unsupplemented aerobiosis with 60% of DO promoted H2O2 and free radical accumulation. Respiration improved the survival to oxidative and freeze-drying stresses, while significant numbers of dead, damaged and viable but not cultivable cells were found in unsupplemented aerobic cultures (60% DO). Analysis of gene expression suggested that the activation of aerobic and respiratory pathways occurred during the exponential growth phase, and that O2 and hemin induced, respectively, the transcription of pox and cydABCD genes. Respiratory cultivation might be a natural strategy to improve functional and technological properties of L. casei.

Effect of adjuncts on microbiological and chemical properties of Scamorza cheese

Scamorza is a semi-hard, pasta filata cheese resembling low-moisture Mozzarella cheese, with a short ripening time (<30d). Scamorza has a bland flavor and, to provide diversification from similar cheeses, it was manufactured using 2 types of milk in the current study: 100% Italian Friesian milk (F) or 90% F and 10% Jersey cow milk (mixed, M), and 2 types of starter: Streptococcus thermophilus or S. thermophilus with peptidolytic Lactococcus lactis, Lactobacillus helveticus, and Lactobacillus paracasei strains as adjuncts). The cheeses were ripened for 30d. The adjunct did not significantly affect acid production or growth of the primary starter; 2 of the species used in the adjunct (Lb. paracasei and Lb. helveticus) rapidly colonized the cheese and persisted until the end of ripening, whereas the counts of nonstarter lactic acid bacteria in the control cheese were low until the end of ripening. The use of adjuncts affected pH, microbial composition (as assessed by both culture-dependent and culture-independent methods), total free amino acid content, and volatile profile (measured using an electronic nose), whereas milk type had only a minor effect. Although differences in primary proteolysis were found, they were probably indirect and related to the effects on pH and moisture. We conclude that, even with a short ripening time (30d), use of a peptidolytic adjunct may significantly affect important features of Scamorza and may be used to create a product that is measurably different from competing products.

Preparation and characterization of microencapsulated phytosterols for the formulation of functional foods: Scale up from laboratory to semi-technical production

Phytosterols were microencapsulated by spray drying in a shell represented by WPI, inulin and chitosan at four different combinations through the formulation of aqueous suspensions. Moreover, two concentrations of Tween 80 (1.25% and 2.50% w/w) and two inlet temperatures (125 °C and 155 °C) were tested. The effect of the different experimental conditions on the process yield and on the microcapsules properties was evaluated. A significant effect of all variables on the microcapsule properties was found. Accordingly, the best performance, with the maximum loading capacity of 25%, was obtained by using only WPI as shell material, Tween 80 at 1.25% and inlet temperature of 155 °C. The process was successfully scaled-up from laboratory equipment to a semi-technical scale keeping the optimal shell formulation and process conditions.

Processing Plants and Technologies for a Sustainable Mediterranean Food Chain

The growing demand of fresh fruit and vegetable, free of pathogens and chemical residues, requires the application of safe and sustainable technologies for extending the storage life of these products. Furthermore, a very interesting and profitable activity is the isolation/extraction of pure natural (herbal) components that could be used by food, pharmaceutical, and cosmetic companies. In this context, several technologies have been developed in order to preserve fruits and vegetables during postharvest, also by using biocontrol agents, natural antimicrobials, GRAS (Generally Recognized As Safe) agents and physical treatments, and to recover valuable compounds as essential oil (from leaf, skin, pulp, or seed) using the most appropriate technology (extraction, distillation, or drying). In this chapter, authors, focusing on some of Mediterranean basin productions that are components of the Mediterranean diet, describe the main sustainable and innovative technologies and the related plants, suitable for management of fruits and vegetables postharvest and for recovery of essential oils from plant materials.