Vanessa Martins da Silva

Optimization of the enzymatic hydrolysis of mussel meat.

UNLABELLED Mussel meat was subjected to enzymatic hydrolysis using Protamex. The relationship of temperature (46 to 64 degrees C), enzyme : substrate ratio (0.48% to 5.52%), and pH (6.7 to 8.3) to the degree of hydrolysis were determined. The surface response methodology showed that the optimum conditions for enzymatic hydrolysis of mussel meat were pH 6.85, temperature 51 degrees C, and enzyme : substrate ratio of 4.5%. Under these conditions a degree of hydrolysis of 26.5% and protein recovery of 65% were obtained. The produced hydrolysate, under optimum condition, was characterized in terms of chemical composition, electrophoretic profile, and amino acid composition. PRACTICAL APPLICATION The practical application of mussel meat hydrolysate is its use as flavoring in products such as soups, sauces, and special beverages. In addition, the product is partially digested and has great nutritional value due to its good amino acid profile and thus can be used as a food supplement in special diets.

Spray dried microparticles of chia oil using emulsion stabilized by whey protein concentrate and pectin by electrostatic deposition

Chia seed oil has a high content of α-linolenic acid (60%) and linoleic acid (20%). Use of this oil in different products is limited due to its liquid state, and the presence of insaturation is a trigger for oxidation. In this context, to facilitate the incorporation of chia oil in food products and increase its protection against oxidation, the aim of this work was to produce chia oil microparticles by spray drying using emulsions stabilized by whey protein concentrate (ζ-potential +13.4 at pH3.8) and pectin (ζ-potential -40.4 at pH3.8) through the electrostatic layer-by-layer deposition technique and emulsions prepared with only whey protein concentrate. Emulsions stabilized by whey protein concentrate and stabilized by whey protein concentrate-pectin were prepared using maltodextrin (10 DE) and modified starch (Hi-Cap® 100). They were characterized in relation to stability, droplet size, ζ-Potential and optical microscopy. The microparticles were characterized in relation to moisture content, water activity, particle size, microstructure and oxidative stability by the Rancimat method. Emulsions stabilized by whey protein concentrate-pectin with added maltodextrin 10 DE and emulsions stabilized by whey protein concentrate with added modified starch (Hi-Cap® 100) were stable after 24h. Emulsions stabilized by whey protein concentrate and by whey protein concentrate-pectin showed droplets with mean diameter ranging from 0.80 to 1.31μm, respectively and ζ-potential varying from -6.9 to -27.43mV, respectively. After spray drying, the microparticles showed an mean diameter ranging from 7.00 to 9.00μm. All samples presented high encapsulation efficiency values, above 99%. Microparticles produced with modified starch showed a smoother spherical surface than particles with maltodextrin 10 DE, which presented a wrinkled surface. All microparticles exhibited higher oxidative stability than chia oil in pure form.

Influence of Carrier Agents on the Physicochemical Properties of Mussel Protein Hydrolysate Powder

The objective of this work was to evaluate the influence of carrier agents, maltodextrin 10 dextrose equivalent (DE) and gum arabic, on the physicochemical properties of mussel meat protein hydrolysate powder produced by spray drying. Hydrolysate was obtained by enzymatic hydrolysis using Protamex (Novozymes, Bagsvaerd, Denmark) and was carried out at 51°C, 4.5 g enzyme/100 g protein, and pH 6.85. The hydrolysate, without and with 15 and 30% of carrier agent, was spray dried at 180°C inlet air temperature and 0.8 L/h feed flow rate. Moisture content, hygroscopicity, particle size, glass transition temperature, morphology, antioxidant capacity, and volatile loss of powders were evaluated. Powder moisture content decreased with the increase in carrier agent concentration. Glass transition temperature increased with carrier agent addition and consequently powder hygroscopicity was reduced, increasing its physical stability. Higher feed solution viscosity was obtained for 30% of maltodextrin and 15 and 30% of gum arabic. The particles obtained from these solution presented a greater number of dents and larger particle size. The use of carrier agents reduced volatile loss and preserved the powders antioxidant capacity.

Water Sorption and Glass Transition Temperature of Spray-Dried Mussel Meat Protein Hydrolysate

The water sorption behavior at 25°C and glass transition temperature (T g ) of mussel meat protein hydrolysate powder without and with maltodextrin 10 DE or gum arabic at 15 and 30% (w/w) were studied in this work. The sorption isotherms were determined by the gravimetric method, and the glass transition temperature was obtained by differential scanning calorimetry (DSC) after powder conditioning at various water activities. Sorption isotherms data were well fitted by a modified Brunauer-Emmett-Teller (BET) model. Powder without additives showed the highest water adsorption followed by those produced with 15 and 30% of carrier agent, respectively. The Gordon-Taylor model was able to predict the effect of water on the glass transition temperature. At 25°C, the critical water content that ensured the glassy state of the mussel hydrolysate powder during storage increased from 0.05 to 0.12 g water/g product and the critical water activity increased from 0.24 to 0.60 when the concentration of carrier agents was increased to 30%.

Performance of different process additives on the properties of mango powder obtained by drum drying

ABSTRACT The use of process additives was evaluated in the drum drying of commercial mango pulp, using corn starch, maltodextrin 10/20 DE, and glyceryl monostearate (GMS). The mass flow rate (MFR) and some powder properties were analyzed: moisture content, vitamin C, total phenolic compounds, carotenoids, β-carotene, glass transition temperature (Tg), hygroscopicity, solubility, color, rheological behavior and color of reconstituted pulp. The pulps presented non-Newtonian and pseudoplastic fluid behavior, while Tg values ranged from 29°C to 38°C. The process performed with 3% corn starch and 0.5% GMS (dry basis) resulted in greater MFR (8.0 ± 0.2 kg/h m2) and vitamin C retention (61.0 ± 0.7%).

Stabilization mechanisms of oil-in-water emulsions by Saccharomyces cerevisiae.

A multiphase system is commonly formed during the oil production by microbial route, which can lead to stable emulsions hindering product recovery. Thus, this study aimed to investigate the mechanisms of emulsion stabilization by the yeast Saccharomyces cerevisiae in order to contribute with processes development of oil production by fermentation. A model system using hexadecane as oil phase and yeast suspension as aqueous phase was used to prepare O/W emulsions. The yeast was subjected to different treatments as inactivation (autoclaving) and washing before to be resuspended in water. The washing water (water from the first washing) and suspension of commercial yeast (active) were also used as aqueous phase. After 24h of preparation, the emulsions separated into three phases: top (cream), intermediate, and bottom phase. The top or cream phase was a concentrated emulsion that kept stable during seven days, except for those prepared from washed yeast that were stable only for a short period of time. Emulsions prepared with washed yeast showed higher cell adhesion to the droplets interface, which implied in a higher amount of yeast into the cream phase in comparison to other formulations. Therefore, yeast cells adhesion plays a role on emulsion stability, but the greater contribution was provided by cell material dispersed into the aqueous phase, regardless of cell viability.

Drying of sicilian lemon residue: influence of process variables on the evaluation of the dietary fiber produced

In this study, the effect of the process variables of the air-drying of Sicilian lemon residues on some technological properties of the fibers produced was studied. The determination and modeling of desorption isotherms were used to establish the equilibrium moisture content at 60, 75, and 90 °C using the static method with 8 saturated salt solutions. The best fit was obtained with BET and GAB models. The drying process was conducted in a vertical tray dryer and delineated according to a central composite experimental design (22) using the following as factors: air velocity (0.5, 0.75 and 1 m/s) and temperature (60, 75, and 90 °C), and it presented a good fit to the exponential model (R2 > 99.9%). The experimental design responses evaluated were the technological properties of the fibers: water-holding, oil-holding, and swelling capacity. Since these properties were present in high levels, the lemon residues could be used to increase content of fibers in foods resulting in the addition of nutritional benefits for the consumers.

Chitosan coated nanostructured lipid carriers (NLCs) for loading Vitamin D: A physical stability study

A nanostructured lipid carrier (NLC) has been developed as a loading system for Vitamin D (VD). The NLCs were obtained by melt-emulsification method and coated with chitosan (CHI) by electrostatic deposition. The lipids used in the formulations were selected in order to provide higher encapsulation efficiency. Thermophysical properties of particles were evaluated by differential scanning calorimetry; particle stability was characterized by size distribution, polydispersity index, zeta-potential and light backscattering. The coating over NLCs was carried out by potentiometric titration with CHI at concentrations of 1.0, 1.5, 2.0 and 2.5% (w/v). Stearic (SA) and oleic acids (OA) were the lipids that showed higher compatibility with VD. The NLC 70(SA):30(OA) was the particle with the lowest polydispersity, size variation and less tendency to physical instability during the storage time. This formulation also presented encapsulation efficiency higher than 98%. In the particles coating, CHI adsorption into the colloidal dispersion provided an initial electrostatic stabilization of the system. A long-term steric barrier was established through further incorporation of CHI. Coated NLCs showed a core-shell structure and a positive zeta-potential (+30 mV), remaining stable for 60 days at 25 °C. During storage time, no expulsion of VD out of the particle was observed.