R. Morales-Medina

Functional and antioxidant properties of hydrolysates of sardine (S. pilchardus) and horse mackerel (T. mediterraneus) for the microencapsulation of fish oil by spray-drying.

The functionality of fish protein hydrolysates (FPH) for the microencapsulation of fish oil was investigated. Muscle protein from sardine (Sardina pilchardus) and horse mackerel (Trachurus mediterraneus) was hydrolysed using Alcalase or trypsin. Physically stable emulsions suitable for spray-drying were obtained when using FPH with a degree of hydrolysis of 5%. Microencapsulation efficiency amounted to 98±0.1% and oxidative stability of the encapsulated oil over a period of twelve weeks was in a similar range as it is reported for other matrix systems. Therefore, the suitability of FPH for use in spray-dried emulsions has been shown for the first time. Since no clear correlation between the antioxidative activity of the FPH and the course of lipid oxidation could be established future research is required to more specifically characterise the molecular structure of the peptides and its impact on protein alteration and role in lipid oxidation.

Production of resistant starch by enzymatic debranching in legume flours.

Resistant starch (RS) was produced by enzymatic hydrolysis of flours from five different legumes: lentil, chickpea, faba bean, kidney bean and red kidney bean. Each legume was firstly treated thermally, then hydrolyzed with pullulanase for 24h at 50°C and pH 5 and lyophilized. At the end of each hydrolysis reaction, the RS amount ranged from 4.7% for red kidney beans to 7.5% for chickpeas. With respect to the curves of RS against hydrolysis time, a linear increase was observed initially and a plateau was generally achieved by the end of reaction. These curves were successfully modeled by a kinetic equation including three parameters: initial RS, RS at long operation time and a kinetic constant (k). Furthermore, the relative increase in hydrolysis, calculated using the kinetic parameters, was successfully correlated to the percentage of amylose.

Development of an up-grading process to produce MLM structured lipids from sardine discards

The aim of the work was to produce MLM structured lipids with caprylic acid (M) as medium chain fatty acid located at the external bonds of the glycerol backbone and concentrated polyunsaturated fatty acids (L) from sardine discards (Sardine pilchardus) in the central bond of the glycerol. To that end, the following steps were conducted: (i) fish oil extraction, (ii) Omega-3 free fatty acids (FFA) concentration (low temperature winterization), (iii) two-steps enzymatic esterification and (iv) triacylglycerols (TAG) purification (liquid column chromatography). The resultant purified triacylglycerols accomplished with the oxidative state (peroxide and anisidine value, PV and AV) required for refined oils. As enzymatic treatment, Omega-3 concentrate FFA (Omega-3>600mg Omega-3 per g oil) were esterified with dicaprylic glycerol employing Novozyme 435. This process presented high regioselectivity, with ∼80mol% of concentrated fatty acids esterified at the sn-2 position.

A lumped model of the lipase catalyzed hydrolysis of sardine oil to maximize polyunsaturated fatty acids content in acylglycerols

The aim of this work was to produce diacylglycerols (DAG) and monoacylglycerols (MAG) with a high content of polyunsaturated fatty acids (PUFA). Rhizomucor miehei lipase mediated-hydrolysis of sardine oil was conducted at several water activities. The system was mechanistically modeled to predict the time evolution of the concentration of triacylglycerols, DAG, MAG and free fatty acids (FFA) and the concentration of saturated, mono- and polyunsaturated fatty acids. The release of the first fatty acid from the triacylglycerol was independent on the unsaturation degree. Contrary, the hydrolysis of the second one was highly affected by the degree of unsaturation, PUFA being the fatty acids that showed the highest resistance to hydrolysis. MAG percentage was maximum (7mol%) at lower water activities, while DAG content was favored at higher water activities (35mol%), achieving a 2-fold concentration of DHA.

Fish Discards as Source of Health-Promoting Biopeptides

Abstract The vast diversity of marine organisms is a source of enormous potential for obtaining bioactive compounds for use in the food industry. In this context, discards, which are defined as the fraction of the fish catch that is not retained onboard but rejected to the sea due to commercial standards, fishing regulations, or them being nontarget species, are regarded as a waste of resources and an environmental problem. The new EU Common Fisheries Policy introduced a discard ban for pelagic species on January 1, 2015. The composition of discarded materials (1%–18% lipids and 15%–20% proteins) means that they are receiving increased attention for their use in biotechnological applications. The six species studied in this chapter, namely, the axillary seabream ( Pagellus acarne ), small-spotted catshark ( Scyliorhinus canicula ), sardine ( Sardina pilchardus ), horse mackerel ( Trachurus mediterraneus ), bogue ( Boops boops ), and blue whiting ( Micromesistius poutassou ), represent more than 85% of the total discards in the Alboran Sea. This chapter mainly focuses on upgrading the protein fraction of the aforementioned species into biopeptides. To this end, compacting and separation stages were designed to obtain the lipid and protein fractions. The influence of enzymatic hydrolysis on the antihypertensive, antioxidant, anticholesterolemic, and antimicrobial activities of the proteins was also analyzed. In addition, the bioavailability of the biopeptides was analyzed using simulated gastrointestinal digestion. Finally, the methods employed for the characterizing and identification of the active peptides are also described. These biopeptides can be employed in the formulation of functional food.