Stella Plazzotta

Combined high-power ultrasound and high-pressure homogenization nanoemulsification: The effect of energy density, oil content and emulsifier type and content

Combinations of ultrasound (US) and high-pressure homogenization (HPH) at low-medium energy densities were studied as alternative processes to individual US and HPH to produce Tween 80 and whey protein stabilized nanoemulsions, while reducing the energy input. To this aim, preliminary trials were performed to compare emulsification efficacy of single and combined HPH and US treatments delivering low-medium energy densities. Results highlighted the efficacy of US-HPH combined process in reducing the energy required to produce nanoemulsions stabilized with both Tween 80 and whey protein isolate. Subsequently, the effect of emulsifier content (1-3% w/w), oil amount (10-20% w/w) and energy density (47-175 MJ/m3) on emulsion mean particle diameter was evaluated by means of a central composite design. Particles of 140-190 nm were obtained by delivering 175 MJ/m3 energy density at emulsions containing 3% (w/w) Tween 80 and 10% (w/w) oil. In the case of whey protein isolate stabilized emulsions, a reduced emulsifier amount (1% w/w) and intermediate energy density (120 MJ/m3) allowed a minimum droplet size around 220-250 nm to be achieved. Results showed that, in both cases, at least 50% of the energy density should be delivered by HPH to obtain the minimum particle diameter.

Exploitation of lettuce waste flour to increase bread functionality: effect on physical, nutritional, sensory properties and on consumer response

Phenol and fibre-rich flour obtained by air-drying and grinding of lettuce waste was partially substituted (26, 53, 170 and 575 g kg ) to wheat flour to produce functional bread. The addition of flour progressively decreased dough leavening capacity while increased bread moisture and firmness. Lettuce waste flour significantly increased the polyphenolic content (up to 3.4 g GAE kg ) of bread samples and enhanced their antioxidant activity by 200%. Bread containing 170 and 575 g kg 1 of lettuce waste flour presented sensory properties and consumer acceptability comparable to those of commercial wholemeal bread with similar rye bran content. Bread containing at least 170 g kg 1 of lettuce waste flour could be associated to nutritional claims related to its enhanced fibre content (>30 g kg ). Data obtained by conjoint analysis demonstrate the possibility of increasing consumer preference for lettuce waste flour bread by proper nutritional (fibre content) and sustainability (lettuce waste valorisation) claims.

Treatment of Food Industry Wastewater With Ultrasound: A Big Opportunity for the Technology

Abstract Considering the growing concerns about wastewater management in the food industry, new strategies are increasingly under study. Among them, ultrasound has been proposed for industrial wastewater treatment. This technology has been applied for water disinfection and decontamination and as a pretreatment prior to anaerobic digestion for biogas production. Ultrasound treatment alone did not reduce the microbial load of wastewater nor completely degrade pollutants. However, its combination with other strategies, including thermal treatment, addition of oxidizing agents, filtration, and adsorption, has been successfully applied for wastewater treatment.