Nannochloropsis is well appreciated in aquaculture due to its nutritional value and the ability to produce valuable chemical compounds, such as pigments (zeaxanthin, astaxanthin. . .) and polyunsaturated fatty acids (EPA). Commercial exploitation needs high cell densities but the low growth rate and the small size of cells are practical difficulties. To increase biomass concentration the positive effect of several factors was evident: (i) pH:/8 control (with dilute Tris Á/HCl buffer); (ii) the continuous illumination (no evidence of photo-inhibition was observed); (iii) a quite large temperature range (259/5 8C); (iv) the presence of organic carbon source (with the danger of contamination); (v) the presence of urea as an additional nitrogen source (10 mM); (vi) a small air flow rate with large bubbles can be more efficient for CO 2 mass transfer (associated to reduced shearing). #

Valorization of food industry waste and plant residues represents an attractive path towards obtaining biodegradable materials and achieving “zero waste” goals. Here, melanin was isolated from watermelon (Citrullus lanatus) seeds and used as a modifier for whey protein concentrate and isolate films (WPC and WPI) at two concentrations (0.1% and 0.5%). The modification with melanin enhanced the ultraviolet (UV) blocking, water vapor barrier, swelling, and mechanical properties of the WPC/WPI films, in addition to affecting the apparent color. The modified WPC/WPI films also exhibited high antioxidant activity, but no cytotoxicity. Overall, the effects were melanin concentration-dependent. Thus, melanin from watermelon seeds can be used as a functional modifier to develop bioactive biopolymer films with good potential to be exploited in food packaging and biomedical applications.

Nannochloropsis, a green microalga, is source for commercially valuable compounds as extensively described and, in particular, is recognized as a good potential source of EPA (20:5v3), an important polyunsaturated fatty acid for human consumption for prevention of several diseases. Climate change might include variation in the UV levels, as one of the consequences derived from the antropogenic activity. This paper shows the response of Nannochloropsis cultures exposed for 7 days to UV-A added to PAR. Growth rates and photosynthetic activity were assessed to determine the impact of UV-A increased levels on the cell growth and basic metabolism activity. Xanthophyll pigments (zeaxanthin and violaxanthin), carotenoids (cantaxanthin and β-carotene) and PUFAs (miristic, palmitic, palmitoleic, araquidonic and eicosapentanoic acids) were measured for assessing the antioxidant response of the microalgae to added UV-A radiation to PAR. The results show that the modulated use of UV-A radiations can led to increased growth rates which are sustained in time by an increased light transduction activity. The expected antioxidant response to the incident UV-A radiation consisted of increases in zeaxanthin and β-carotene contents -synthesis of antioxidant carotenoids-and increases in the SFAs (saturated fatty acids) to PUFAs (polyunsaturated fatty acids) ratio. The results suggest that modulated UV-A radiation can be used as a tool to stimulate value molecules accumulation in microalgae through an enhanced both light transduction process and antioxidant response, while sustaining cell growth.

No abstract

Frozen yogurt is a type of dairy product that is considered to be a more healthful alternative to conventional ice cream due to its lower fat content and the presence of viable lactic acid bacteria. Lactose-free products are a growing trend in the dairy industry, and lactose-free yogurts and ice creams can both be found on the market. However, lactose-free frozen yogurt has not yet reached the market. In this study, we aimed to investigate the effect of adding κ-carrageenan (0.05, 0.1, and 0.15%) and corn starch (1, 2, and 3%) on acidity, texture, viscosity, overrun, melting properties, color attributes, and sensory characteristics of lactosefree frozen yogurts. Lactose was reduced by enzymatic hydrolysis during the fermentation process. The effectiveness of the hydrolysis was measured by HPLC, and lactose was reduced to 0.05% after 80 min of incubation with the enzyme. The addition of stabilizers did not change overrun and melting properties of frozen yogurt, but it did affect pH, titratable acidity, and color parameters. The product with 0.15% κ-carrageenan had the highest hardness and stickiness values. Moreover, κ-carrageenan had a positive effect on sensory attractiveness of lactose-free frozen yogurt, and it reduced the coarse texture in comparison with the control without stabilizers. A lactose-free frozen yogurt with good quality and nutritional characteristics was produced, particularly with the use of κ-carrageenan as stabilizer.

The production and incorporation of liquid whey protein concentrates (LWPCs) in fresh cheese and set yogurt is proposed as a solution for immediate reutilization of whey produced by small-and medium-scale dairy plants avoiding expensive processing steps (e.g., evaporation and drying) for the recovery of this by-product. Accordingly, the incorporation of LWPCs in such products was performed in order to compare the functional and sensorial properties of modified products with the conventional ones. The use of LWPC in fresh cheese increased water-holding capacity as well as product stability during storage. Fresh cheese hardness, chewiness, and gumminess decreased during storage in a more pronounced way in products with LWPC. The fat content influences significantly all the physicochemical properties tested in set yogurts. Incorporating LWPC in set yogurts does not produce appreciable differences in the visual properties when considering products with medium-fat content, but these differences become significant for full-fat yogurts. Adhesiveness and springiness were not significantly affected with storage time or by the amount of LWPC incorporated for medium-fat yogurts. Higher values of hardness and gumminess were obtained for full-fat yogurts, but these parameters decreased with LWPC incorporation. Syneresis was reduced using LWPC but increased with storage time. During storage, viscosity differences between LWPC incorporated yogurts and the conventional ones were only maintained in the case of creamy yogurts. The sensory panel detected differences between conventional and modified products in the case of fresh cheeses but no significative differences were detected between yogurts. LWPCs can be a good alternative to conventional dry products used in fresh cheese and set yogurt manufacture since their utilization reduces milk consumption and allows for the increase in total solids content. Additionally, their incorporation in milk originates end products with attractive physicochemical and sensorial characteristics at lower production costs.

This work focuses on the production of liquid whey protein concentrates by ultrafiltration followed by thermal denaturation and homogenization of the ultrafiltrated concentrate, as well as on the production of ultrafiltrated permeates concentrated by reverse osmosis. Kefir grains (fresh and thawed) and/or commercial probiotic bacteria were inoculated in both liquid whey protein concentrates and concentrated ultrafiltrated permeates and grown at 25 °C for 24 h for the manufacture of fermented drinks. The physicochemical characterization (pH, titratable acidity, viscosity, and content of total solids, ash, fat and proteins) of the obtained drinks was then assessed and compared. Enumeration of viable microorganisms was carried out immediately after inoculation (at 0 h), during the fermentation period (at 12 and 24 h) and during refrigerated storage (at 48, 168 and 336 h). The fermented drinks showed acceptable physicochemical and sensorial properties, and contained above 7 log CFU/mL of lactococci and lactobacilli and 6 log CFU/mL of yeasts after 14 days of refrigerated storage, which is in agreement with the standards required by international organizations like European Food Safety Authority (EFSA) and Food and Drug Administration (FDA) for products containing probiotics. In summary, the strategy developed in this work contributes to the expansion of the applications of products derived from whey fractionation for the design of novel functional foods.

No abstract