Development of Fish Oil-Loaded Microcapsules Containing Whey Protein Hydrolysate as Film-Forming Material for Fortification of Low-Fat Mayonnaise

The authors are very grateful to Lis Berner for her skillful help with the PV and SVOP measurements of the microcapsules.The influence of the carbohydrate-based wall matrix (glucose syrup, GS, and maltodextrin, MD21) and the storage temperature (4 ◦C or 25 ◦C) on the oxidative stability of microencapsulated fish oil was studied. The microcapsules (ca. 13 wt% oil load) were produced by spray-drying emulsions stabilized with whey protein hydrolysate (WPH), achieving high encapsulation efficiencies (>97%). Both encapsulating materials showed an increase in the oxidation rate with the storage temperature. The GS-based microcapsules presented the highest oxidative stability regardless of the storage temperature with a peroxide value (PV) of 3.49 ± 0.25 meq O2/kg oil and a content of 1-penten-3-ol of 48.06 ± 9.57 ng/g oil after six weeks of storage at 4 ◦C. Moreover, low-fat mayonnaise enriched with GS-based microcapsules loaded with fish oil and containing WPH as a film-forming material (M-GS) presented higher oxidative stability after one month of storage when compared to low-fat mayonnaise enriched with either a 5 wt% fish oil-in-water emulsion stabilized with WPH or neat fish oil. This was attributed to a higher protective effect of the carbohydrate wall once the microcapsules were incorporated into the mayonnaise matrix.Spanish Ministry of Science, Innovation and Universities CTQ2017-87076-R PRE2018-08486

Antioxidant activity of protein hydrolysates obtained from discarded Mediterranean fish species

In this study, five discarded species in the Mediterranean Sea, namely sardine, horse mackerel, axillary seabream, bogue and small-spotted catshark, were evaluated as raw material for obtaining fish protein hydrolysates exhibiting antioxidant activity. The DH of the hydrolysates ranged from 13.2 to 21.0%, with a protein content varying from 60.7 to 89.5%. The peptide profile of all hydrolysates was very similar, except for the hydrolysate of small-spotted catshark. Their lipid content was found to be between 4.6 and 25.3%. The highest DPPH scavenging activity was found for the hydrolysates of sardine and horse mackerel with EC50 values varying from 0.91 to 1.78 mg protein/mL. Sardine and small-spotted catshark hydrolysates exhibited the highest ferrous chelating activity with an EC50 value of 0.32 mg protein/mL. Moreover, sardine and bogue hydrolysates presented the highest reducing power. Finally, a total of six antioxidant peptides were theoretically identified within the structure of myosin and actin proteins from sardine and small-spotted catshark. The potential antioxidant activity exhibited by the hydrolysates suggests that it is feasible to obtain added-value products such as natural antioxidants from these discarded species.This work was supported by the Spanish National Plan I + D + i (projects CTQ2008-02978 and CTQ2011-23009) and by Santander Bank (grant for young researchers

Antioxidant peptides from goat milk protein fractions hydrolysed by two commercial proteases

Goats' milk microfiltration fractions were hydrolysed with subtilisin or trypsin, or both, and tested for 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging capacity, iron chelation capacity, and inhibition of secondary oxidation products formation in liposomes. The retentate treated with subtilisin was most active regarding radical scavenging capacity (SC50 ≈ 4 μg mL−1), while the permeate treated with subtilisin exhibited the best iron chelation capacity (IC50 ≈ 65 μg mL−1) and prevention of secondary lipid oxidation products formation (33% inhibition at 25 μg mL−1). In the retentate hydrolysate various active peptides were identified. Tyrosine seemed fundamental in the ABTS radical scavenging capacity of the peptides, and also to play a role in the inhibition of formation of secondary lipid oxidation products, in which phenylalanine seemed to play the key role. Non-protein compounds in the permeate hydrolysate seemed more important than peptides for the antioxidant activities detected.Consejería de Economía, Innovación, Ciencia y Empleo of Junta de Andalucía (TEP-02579)Danish Council for Strategic Research (NOVENIA project

Proceso de mentorizaciónen el Departamento de Ingeniería Química de la Universidad de Granada

La Universidad de Granada al igual que otras universidades, consideran que deben garantizar la cualificación de su profesorado de acuerdo a la adaptación al EEES. Como consecuencia del plan de formación del profesorado principiante en esta universidad, surgió un grupo docente en el Departamento de Ingeniería Química formado por 4 docentes noveles y una profesora mentora, para trabajar conjuntamente en la formación de los mencionados noveles para la mejora de su actividad docente. La experiencia durante los 2 cursos académicos de mentorización ha resultado muy positiva, destacando las bondades que aporta el trabajo en grupo al proceso de mentorización

Angiotensin I-converting enzyme inhibitory activity of enzymatic hydrolysates of goat milk protein fractions

Casein and whey protein fractions from goat milk were hydrolysed by subtilisin and trypsin, individually and in combination, to release angiotensin converting enzyme (ACE)-inhibitory peptides. Selected hydrolysates were fractionated by size exclusion chromatography (SEC) and further characterised. The highest ACE-inhibitory activity was obtained from the casein fraction hydrolysed by the combination of enzymes. SEC presented 4 fractions with fraction F2 (<2.3 kDa) containing the highest concentration of peptides and the highest activity. F2 contained a number of peptides not previously identified from caprine caseins but with structural similarity to other ACE-inhibitory peptides. The most active fraction in relation to protein content was F4 with IC50 between 9.3 and 5.1 μg mL−1. This fraction contained a compound tentatively identified as WY, an active dipeptide not previously reported from caseins. The high inhibitory capacity of these fractions points towards the advantage of implementing a membrane process to concentrate the most active peptides.Consejería de Innovación, Ciencia y Empresa of Junta de Andalucía (P07-TEP-02579)Danish Strategic Research Council (NOVENIA project