Rikke Miklos

Green tea extract impairs meat emulsion properties by disturbing protein disulfide cross-linking

The dose-dependent effects of green tea extract (100, 500, or 1500ppm) on the textural and oxidative stability of meat emulsions were investigated, and compared to a control meat emulsion without extract. All levels of green tea extract inhibited formation of TBARS as a measure for lipid oxidation. Overall protein thiol oxidation and myosin heavy chain (MHC) cross-linking were inhibited by 100ppm green tea extract without jeopardizing the textural stability, while increasing concentrations of extract resulted in reduced thiol concentration and elevated levels of non-reducible protein modifications. Addition of 1500ppm green tea extract was found to modify MHC as evaluated by SDS-PAGE combining both protein staining and specific thiol staining, indicating that protein modifications generated through reactions of green tea phenolic compounds with protein thiols, disrupted the meat emulsion properties leading to reduced water holding capacity and textural stability. Hence, a low dose of green tea extract preserves both the textural and the oxidative stability of the meat proteins.

Effect of the type of fat on the physicochemical, instrumental and sensory characteristics of reduced fat non-acid fermented sausages.

Four batches of reduced fat non-acid fermented sausages were manufactured with pork-ham lean, and the addition of no fat (Lean), 5% pork backfat (BF), 5% sunflower oil (SO) and 5% diacylglycerols (DAGs). The effect of the type of fat as pork-fat substitute on some physicochemical parameters, instrumental color and texture and sensory attributes of the sausages was studied. Results showed that reduced fat non-acid fermented sausages containing less than 12.5% of fat (BF, SO and DAGs) had a good overall sensory quality. This means a fat reduction of more than 70% compared with the average fat content of standard fermented sausages of similar characteristics. Sausages with SO showed higher sensory ratings in desirable ripened odor and flavor attributes and improved texture defined by lower hardness and chewiness (both sensory and instrumental) and higher crumbliness. Sausages with DAGs showed a similar behavior to that of BF, so they could be a good alternative to produce healthier reduced fat non-acid fermented sausages.

Influence of lipid type on water and fat mobility in fermented sausages studied by low-field NMR.

The effects of diacylglycerols (DAG), pork back fat and sunflower oil on water and fat mobility in fermented sausages were studied with (1)H NMR relaxometry. The added fat affected the physicochemical parameters weight loss, water activity, moisture content and moisture content on a defatted-dry-matter basis of reduced-fat non-acid fermented sausages. The weight losses were the lowest in sausages prepared with DAG and sunflower oil, which resulted in higher water activity compared to sausages prepared with back fat. The relaxation times related to fat mobility differed between fat types and increased in the order: control<DAG<back fat<sunflower oil. The differences in fat mobility were ascribed to differences in the fat distribution caused by deviations in the physicochemical properties of the fat types.

Grating-based X-ray tomography of 3D food structures

A novel grating based X-ray phase-contrast tomographic method has been used to study how partly substitution of meat proteins with two different types of soy proteins affect the structure of the formed protein gel in meat emulsions. The measurements were performed at the Swiss synchrotron radiation light source using a grating interferometric set-up.

SURFACE ACTIVE LIPIDS AS ENCAPSULATION AGENTS AND DELIVERY VEHICLES

Surface active lipids, such as partial acylglycerols, phospholipids, and glycolipids, are amphiphilic molecules that lower either the surface tension of the medium in which they are dissolved or the interfacial tension between phases at which they are adsorbed. Due to their amphiphilicity, surface active lipids are able to self-assemble into various unique supramolecular structures ranging from micro- to nanoscales. These unique supramolecular structures are found to have enhanced physical properties ranging from increased gelation capability, guest molecules loading capacity, and in-vivo stability to targeted delivery and molecular recognition. Thus, surface active lipids have garnered huge interest as encapsulation agents and delivery vehicles in various industries including food, pharmaceutical, and cosmetics. Work has also been directed toward synthesis of novel compounds and structural modification of existing surface active lipids. This chapter presents a review on current state-of-the art design, synthesis, and purification of surface active lipids—partial acylglycerols, phospholipids, glycolipids, aminolipids and lipopeptides, phytosterol surfactant, and antioxidant esters and elucidates physical properties of such lipids, including self-assembling and formation of various supramolecular structures. It also discusses some potential applications of the surface active lipids.