Stabilized soy protein emulsion enriched with silicon and containing or not methylcellulose as novel technological alternatives to reduce animal fat digestion.

During the last decade, the consumption of animal saturated fat has been associated with an increased risk of chronic disease. Experience shows that changing the dietary habits of the population is a complicated and slow process, so technological strategies offer new possibilities for the development of functional foods. The present work is focused on studying the impact of using a food-grade non-ionic hydrocolloid (methylcellulose; MC) and/or the inclusion of silicon (Si) as a bioactive compound in pork lard emulsions stabilized with soy protein concentrate (SPC), on the structure, rheology, lipid digestibility and Si bioaccesibility during in vitro gastrointestinal digestion (GID). Four emulsions (SPC, SPC/Si, SPC/MC and SPC/MC/Si) were prepared with a final biopolymer (SPC and/or MC) concentration of 4% and 0.24% Si. The results showed a lower degree of lipid digestion in SPC/MC compared with SPC, specifically at the end of the intestinal phase. Moreover, Si partially reduced fat digestion only when incorporated into the SPC-stabilized emulsion, while this effect was lost in SPC/MC/Si. This was probably due to its retention inside the matrix emulsion, which resulted in lower bioaccesibility than in SPC/Si. Additionally, the correlation between the flow behavior index (n) and the lipid absorbable fraction was significant, suggesting that n can be a predictive marker of the extent of lipolysis. Concretely, our results revealed that SPC/Si and SPC/MC can be used as pork fat digestion reducers and thus, they can replace pork lard in the reformulation of animal products with potential health benefits.

Development and Physico-Chemical Characterization of Healthy Puff Pastry Margarines Made from Olive-Pomace Oil.

Due to its characteristic aroma and flavor, puff pastry (PP) prepared with butter is more accepted than that made with margarine, yet a high saturated fat consumption is associated with cardiovascular disease. This work studies the potential of olive-pomace oil (OPO) as main ingredient of PP margarines together with different organogelator agents to imitate the technological properties of a commercial fatty preparation (CFP). Rheological and textural properties were measured in all formulated margarines (FM) and, additionally, thermal and microstructural properties, and fatty acid (FA) profiles were analyzed in some selected FM. The different FM had viscous modulus (G″) and loss factor (tan δ) values lower than those of CFP, thus reflecting a different viscoelasticity and plasticity. The crystallization and melting temperatures of FM were also different from those of CFP, indicating the presence of a dissimilar polymorphic fat-crystal structure. Nevertheless, the FM containing an oleogel prepared with 5% beeswax and OPO was more similar to CFP. The FA profile of CFP and FM, with 80% polyunsaturated fatty acids (PUFA) and 60% oleic acid, is healthier than that of a PP commercial butter (CB), evidencing that, although improvements in margarine plasticity are still necessary, OPO is technologically viable to produce healthier PP margarines.

The Influence of Cellulose Ethers on the Physico-Chemical Properties, Structure and Lipid Digestibility of Animal Fat Emulsions Stabilized by Soy Protein.

This study explores the influence of carboxymethylcelullose (CMC) and methylcelullose (MC), added by simultaneous (sim) and sequential (seq) emulsification methods, on the structure, rheological parameters and in vitro lipid digestibility of pork lard O/W emulsions stabilized by soy protein concentrate (SPC). Five emulsions (SPC, SPC/CMC-sim, SPC/CMC-seq SPC/MC-sim, SPC/MC-seq) were prepared in vitro. The presence of CMC and MC, and the stage of incorporation affected the emulsion microstructure. In the SPC emulsion, lipid droplets were entrapped by a protein layer that was thicker when MC was added, providing greater resistance against environmental stresses during gastrointestinal digestion. At 37 °C, CMC incorporation produced a structural reinforcement of the SPC emulsion, whereas MC addition did not affect the network rigidity, although a delaying effect on the crossover temperature was observed, which was more evident in SPC/MC-seq. The presence and stage of CMC and MC incorporation affected the rate and extent of lipolysis, with SPC/MC-seq presenting an inferior concentration of free fatty acids. The lower extent of lipolysis observed in SPC/MC-seq may be positive in the manufacture of animal fat products in which reduced fatty acid absorption is intended.

New Alternatives in Seafood Restructured Products.

A general overview, focusing on new trends in the different techniques used in restructured seafood product processing has been described in this work. Heat-induced gelation has been more widely studied in scientific literature than cold gelation technology. This latter technology includes the use of hydrocolloids (alginates and glucomannan) or enzymes (microbial transglutaminase) for making both raw and cooked restructured products. In restructuration processes, fortification processing with some functional ingredients is studied, giving as a result extra value to the products as well as increasing the variety of new seafood products. The process of alleviating heavy metals and organic pollutants from the raw material used has also been reviewed in the present paper.

Effects of Magnetic Fields on Freezing: Application to Biological Products.

Magnetic freezing is nowadays established as a commercial reality mainly oriented towards the food market. According to advertisements, magnetic freezing is able to generate tiny ice crystals throughout the frozen product, prevent cell destruction, and preserve the quality of fresh food intact after thawing. If all these advantages were true, magnetic freezing would represent a significant advance in freezing technology, not only for food preservation, but also for cryopreservation of biological specimens such as cells, tissues, and organs. Magnetic fields (MFs) are supposed to act directly on water by orientating, vibrating, and/or spinning molecules to prevent them from clustering and, thus, to promote supercooling. However, many doubts exist about the real effects of MFs on freezing and the science behind the potential mechanisms involved. To provide a basis for extending the understanding of magnetic freezing, this paper presents a critical review of the materials published in the literature up to now, including both patents and experimental results. After examining the information available, it was not possible to discern whether MFs have an appreciable effect on supercooling, freezing kinetics, ice crystals, quality, and/or viability of the frozen products. Experiments described in the literature frequently fail to identify and/or control all the factors that can play a role in magnetic freezing. Moreover, many of the comparisons between magnetic and conventional freezing are not correctly designed to draw valid conclusions, and wide ranges of MF intensities and frequencies are unexplored. Therefore, more rigorous experimentation and further evidence are needed to confirm or reject the efficacy of MFs in improving the quality of frozen products.

Vitamin C content and sensorial properties of dehydrated carrots blanched conventionally or by ultrasound.

Vitamin C content and sensorial properties have been evaluated in air-dried carrots previously subjected to different ultrasound (US) or conventional blanching pretreatments. In addition, mass spectral fingerprints obtained by the Headspace ChemSensor System have been evaluated for the first time for classification of carrots according to their processing. Conventional blanching treatments at high temperature gave rise to carrots with retention of vitamin C in the range 37.5-85%, whereas carrots blanched conventionally at 60°C and by US-probe at temperatures up to 60 and 70°C showed vitamin C retention values lower than 4%. Regarding sensorial analysis of rehydrated carrots, US-pretreated samples presented acceptable quality, and no statistically significant differences with respect to conventionally blanched carrots, were detected. In spite of this, differentiation of samples processed under comparable intensity conditions and/or with similar composition was possible from their mass spectral fingerprints after chemometric data analysis.

Stability of omega-3 fatty acids in fortified surimi seafoods during chilled storage.

Physical, chemical, and sensory properties of cooked surimi seafood gels (crab analogue) fortified with omega-3 fatty acids (FA) were monitored during chilled storage. Three sources of stabilized omega-3 FA (fish oil concentrate, menhaden oil, and a purified marine oil) were each incorporated into gels to an omega-3 FA content of 1.5 or 2.5%, w/w. Omega-3 FA stability, development of off-flavors, and changes in color and texture were monitored during chilled storage for 2 months. Gels with fish oil concentrate developed fishy flavor and aroma within 30 days and were eliminated from the study. Gels containing menhaden oil and purified marine oil exhibited little change in sensory properties or oxidation products throughout 2 months of storage. Relative polyene index values (ratio of polyunsaturated to saturated fatty acids) indicated that the omega-3 FA were stable at both levels of addition. Omega-3 fortified gels were whiter than control gels, and gel texture was modified when menhaden and purified oils were added but not significantly affected by the level of omega-3 addition.