Protein Fractions from Flaxseed: The Effect of Subsequent Extractions on Composition and Antioxidant Capacity.

Flaxseed proteins exhibit functionalities interesting for the food industry, including antioxidant capacity. Antioxidant activity depends on the protein composition and the presence of phenolic compounds extracted with them from the matrix. The research focused on the effect of subsequent protein extractions (water, salt and alkaline) of flaxseed meals (of three cultivars) on the protein fraction composition and its relations to antioxidant capacity. The protein and phenolic profiles and antioxidant functionalities (in antiradical ORAC and emulsion assays) were analysed. Spectroscopic characteristics of the fractions (fluorometric and FT-IR analysis) were also included. Our study has shown the effect of fractionation on the share of proteins at MW from 56-38 kDa (globulin-like) and <15 kDa (albumin-like) in the protein profiles. The highest globulin share was in the alkaline-extracted fractions (AEF) and albumin in the salt-extracted (SEF) ones. SDG (secoisolariciresinol diglucosides) and phenolic acids (p-coumaric and ferulic) were extracted with flaxseed proteins. Their contents were fraction-dependent and the highest in AEF. The concentration of phenolics in AEF corresponded with the highest antiradical capacity (ORAC) compared with the other fractions. However, the SEF showed a higher ability to inhibit oxidation in emulsions than AEF, which could be associated with the higher content of the low MW proteins.

The Selection of the Optimal Impregnation Conditions of Vegetable Matrices with Iodine.

This study aimed to determine the use of selected vegetables (pumpkin, cauliflower, broccoli, carrot) as carriers of potassium iodide (KI) and potassium iodate (KIO3) by determining changes in iodine content under various conditions of impregnation as the degree of hydration, impregnated sample temperature, and impregnation time. The influence of these conditions on iodine contents in vegetables after their fortification and storage (21 °C/230 days) was analyzed. The results showed that all selected vegetables could be efficient iodine carriers. However, the conditions of the impregnation process are crucial for fortification efficiency, particularly the degree of hydration and the temperature of the impregnated samples before drying. The results showed that the lowest iodine content was in samples fortified at 4 °C and 1:4 hydration. On the other hand, the highest reproducibility of iodine was for the following fortification conditions: temperature of -76 °C and hydration of 1:1. The studies confirmed the higher stability of iodine in KIO3 form compared to KI. To increase recovery of the introduced iodine in the product after drying, using the conditioning step at 4 °C is not recommended. We recommend freezing vegetables immediately after the impregnation process.

Innovative Application of Phytochemicals from Fermented Legumes and Spices/Herbs Added in Extruded Snacks.

A trend related to adding legume seeds to various products has been observed. This work aimed to use fermented red bean/broad bean seeds and their hulls to produce extruded snacks with more beneficial nutritional properties and good sensory quality. Extruded snacks containing fermented ground seeds (50%) or hull (10%) of red bean/broad bean and corn grits with the addition of selected herbs/spices (0.5%) were prepared. The chemical composition, phenolic profile, antioxidant activity, and sensory quality were analysed. The results showed that the protein content ranged from 9 to 22.9 g 100 g-1, phenolic compounds ranged from 3.97 to 12.80 mg 100 g-1 (with the addition of herbs/spices, even up to 62.88 mg 100 g-1), and antioxidant activities ranged from 4.32 to 10.23 Trolox g-1 (ABTS assay), depending on the type of fermented materials. The addition of ground seeds/hull did not influence the consumer desirability, whereas the addition of selected herbs/spices, particularly lovage, increased it. The application of fermented red bean and broad bean seeds and their hulls, as part of the assumptions of the planetary diet, enabled enrichment of extruded corn products, which are often consumed by vegans and vegetarians, with nutritionally valuable ingredients.

The Effect of Roasting on the Protein Profile and Antiradical Capacity of Flaxseed Meal.

Roasting is more and more often used as a pre-treatment of flaxseeds. However, the process can influence flaxseed proteins that may be crucial for their properties. The aim of this research was to study changes in the electrophoretic protein profile (SDS-PAGE) and the antiradical capacity of flaxseed meals after roasting. The roasting temperature (160, 180, and 200 °C) and flaxseed cultivars (golden and brown seed) were factors including in the study. The free (F-MRP) and bound-to-protein (B-MRP) Maillard reaction products were also analyzed. The most significant changes in the SDS-PAGE protein profiles of roasted seeds of each of the tested flax cultivars were observed for the 13 kDa protein fraction (decrease) and for the 19 kDa and 17 kDa fractions (increase). The research revealed a significant correlation between the roasting temperature and B-MRP content, and changes in the percentage share of those three protein fractions. The antiradical capacity of roasted flaxseeds decreased, as compared with untreated seeds. After roasting at 200 °C the antiradical capacity of flaxseeds improved slightly, probably due to the MRP formation, but it was still significantly lower than that of the raw seeds. The research provides novel information about key protein fractions that seem to be important changing during heat treatment.

Sensory Analysis in Assessing the Possibility of Using Ethanol Extracts of Spices to Develop New Meat Products.

The food industry has endeavoured to move toward the direction of clean labelling. Therefore, replacing synthetic preservatives with natural plant extracts has gained significant importance. It is necessary to determine whether products enriched with such extracts are still accepted by consumers. In this study, consumer tests (n = 246) and sensory profiling were used to assess the impact of ethanol extracts of spices (lovage, marjoram, thyme, oregano, rosemary, and basil; concentration 0.05%) on the sensory quality of pork meatballs and hamburgers. The desirability of meat products with spice extracts to consumers depended on the added extract. The highest scores were for products with lovage extract, whose sensory profile was the most similar to the control sample without the addition of an extract (with higher intensity of broth taste compared with the others). Products with rosemary and thyme extracts were characterised by lower desirability than the control. This was related to the high intensity of spicy and essential oil tastes, as well as the bitter taste in the case of products with thyme. The studied extracts of spices allow for the creation of meat products (meatballs and hamburgers) with high consumer desirability, however, the high intensity of essential oil and spicy tastes might be a limitation.

Changes in oxidative stability and protein profile of flaxseeds resulting from thermal pre-treatment.

BACKGROUND: The oxidative stability of oilseeds is crucial for their technological/nutritional quality and shelf life. This research aimed to evaluate the effect of thermal pre-treatment (steaming and roasting under various time/temperature conditions) on flaxseed oil and protein stability. The monitoring of changes in oil oxidation in situ and protein profiles (SDS-PAGE) and analysis of the antiradical activity of ethanolic and aqueous fractions were included in the study. RESULTS: Flaxseed stability during storage was considerably affected by thermal pre-treatment conditions. Dynamics of oil oxidation was accelerated at 160 °C and 180 °C but slowed at 200 °C. Influence of pre-treatment conditions on the antiradical activity of the aqueous fraction was clearly observed and no effect concerning the ethanolic fraction was found. The most significant changes in protein profile of 200 °C-roasted flaxseed were found with the observed disappearance of 19 kDa protein. A treatment-dependent decrease in the 13 kDa protein was also detected. Based on the aqueous extract protein profiles, roasting conditions were found to be crucial for protein extractability. CONCLUSIONS: The study has broadened knowledge of the consequences of flaxseed thermal treatment. The deterioration of flaxseed oil oxidative stability is shown. The changes of 19 and 13 kDa proteins suggest their sensitivity to thermally induced aggregation and/or cross-link. © 2018 Society of Chemical Industry.

Effect of liver pâté enrichment with flaxseed oil and flaxseed extract on lipid composition and stability.

BACKGROUND: There is an increase interest from food technologists in the improvement of the nutritional value of meat products, especially their lipid profile and shelf life. The aim of this study was to determine the effect of animal fat replacement with flaxseed oil (20%) and flaxseed extract addition (0.05%-0.25%) on changes in composition and stability of liver pâté lipid fractions. RESULTS: Replacement of animal fat with flaxseed oil was observed to lower the saturated and monoenoic fatty acid in the product's fatty acid profile by around 12% and to raise the polyene fatty acid contribution by more than 70% when compared to the control. The replacement also resulted in enriching the pâté with phytosterols (ß-sitosterol, campesterol, and cycloartenol). The addition of 0.05% and 0.10% ethanol flaxseed extract significantly slowed down lipid oxidation changes during storage of the pâté. CONCLUSIONS: The study showed that a storage-stable meat product - liver pâté - characterized by a high nutritional value can be designed through the addition of flax oil rich in unsaturated fatty acids and flaxseed extract. The addition of 0.05% of the extract was found to be sufficient to improve the liver pâté's oxidative stability; it can thus be recommended for this type of product. © 2018 Society of Chemical Industry.

Sensory qualities of pastry products enriched with dietary fiber and polyphenolic substances.

BACKGROUND: Growing consumer demand for products with pro-health properties is forcing food manufacturers to introduce new food items onto the market, which will not only possess such health-enhancing properties but will also compete on the grounds of sensory attributes - taste, flavour, texture etc. METHODS: The aim was to evaluate these sensory attributes of pastry products enhanced with biologically active compounds, such as inulin, buckwheat hull and buckwheat flour. For decreasing the energy value of the products tested (crispy cookies, muesli cookies, waffles and pancakes) some ingredients were replaced: vegetable butter or oil by inulin and wheat flour by roasted buckwheat flour and thermally processed buckwheat hull. The substances mentioned are rich sources of soluble and insoluble buckwheat fiber, and also polyphenolic substances. Dry chokeberry and mulberry leaf extract were added as a rich source of flavonoids and 1-deoxynorijimycin, respectively. These substances are recommended for people with obesity. The processing was carried out at 175°C for 15 minutes using a convection oven (Rational Combi-Steamer CCC). RESULTS: Pastry products with buckwheat flour, buckwheat hulls, mulberry extract, chokeberry and inulin had a lower food energy, a higher dietary fiber content and scored high on customer desirability. CONCLUSIONS: Pastry products which contain ingredients carrying biologically active substances are not only attractive from the sensory point of view, but also low in calories, and are thus recommendable for obesity people.

Effect of Extraction Method on the Phenolic and Cyanogenic Glucoside Profile of Flaxseed Extracts and their Antioxidant Capacity.

The application of flaxseed extracts as food ingredients is a subject of interest to food technologists and nutritionists. Therefore, the influence of the extraction method on the content and composition of beneficial compounds as well as anti-nutrients is important. In the study, the effects of two solvent extraction methods, aqueous and 60 % ethanolic, on phenolic and cyanogenic glucoside profiles of flaxseed extract were determined and compared. The impact of extracted phenolic compounds on the antioxidant capacity of the extracts was also investigated. Defatted meals from brown and golden flax varieties were used as extraction material. The ethanolic extraction was more selective for phenolics (100.8-131.7 mg g-1) than the aqueous one (11.5-15.7 mg g-1). However, the contribution of particular phenolic compounds to total phenolics was much more dependent on flax variety than extraction method. A strong relationship was observed between both radical scavenging and ferric reducing activity and the content of phenolics (particularly secoisolariciresinol diglucoside). The correlation between extract chelating ability and phenolics was moderate suggesting that other flaxseed compounds are involved in this activity. The extraction method strongly affected cyanogenic glucoside content of flaxseed extracts; the aqueous extraction caused 96 % reduction in cyanogenic glucoside content (0.56-0.62 mmol g-1) when compared to the content in defatted meal (9.1-11.6 mmol g-1). On the contrary, ethanolic extraction resulted in the high cyanogenic glucoside content in the extracts (71-89 mmol g-1). The results reveals that ethanolic extraction gives extracts rich in antioxidant lignans; aqueous extracts have lower antioxidant activity than ethanolic but cyanogenic glucosides are significantly reduced.

Effect of Flaxseed Meals and Extracts on Lipid Stability in a Stored Meat Product.

Flaxseeds have been recently in focus due to the antioxidant capacity of some of their compounds. However, there is a lack of easily accessible information concerning their activity against lipid oxidation in food systems. Therefore, the aim of the study was to determine the effect of defatted meals (DFM) and the aqueous extracts (AFE) obtained from brown and golden flaxseeds on lipid oxidation in pork meatballs. Fatty acid composition, peroxide value (PV), thiobarbituric acid reactive substances (TBARS) and cholesterol content were monitored during 6 months of freezer storage. Cholesterol oxidation products were identified and quantified. Both DFM and AFE limited fatty acid and cholesterol oxidation during meatball storage. Their antioxidant effect depended on flax variety (brown or golden) and preparation type (DFM or AFE). Lower level of PV and TBARS, compared with the ones with AFE, were noted in meatballs with DFM. Both DFM and AFE, from the brown seed variety, protect the lipids against oxidation to a higher extent. During the storage, a cholesterol degradation was observed. AFE (particularly from the brown variety) limited changes in cholesterol content. Moreover, they stabilized fatty acid composition of stored meatballs. However, DFM efficiently inhibited cholesterol oxidation.

Effect of ethanolic flax (Linum usitatissimum L.) extracts on lipid oxidation and changes in nutritive value of frozen-stored meat products.

BACKGROUND: Flaxseed (Linum usitatissimum L.) is an important source of phenolic compounds, mainly lignans. Antioxidant capacities of flaxseed extracts that contain the compounds have been reported earlier. However, there is a lack of accessible information about their activity against lipid oxidation in meat products. Therefore, the effect of ethanolic flaxseed extracts (EFEs) on lipid stability and changes in nutritive value of frozen-stored meat products (pork meatballs and burgers) was determined. MATERIAL AND METHODS: EFEs from three Polish flax varieties (Szafir, Oliwin, Jantarol) were applied in the study. During 150-day storage of meat products, the lipid oxidation (peroxide and TBARS value) and thiamine retention were periodically monitored, alongside with methionine and lysine availability and protein digestibility. RESULTS: The addition of EFEs significantly limited lipid oxidation in stored meatballs and burgers. EFE from brown seeds of Szafir var. was superior to the others from golden seeds of Jantarol and Oliwin. Moreover, the extracts reduced changes in thiamine and available lysine content, as well as protein digestibility, during storage time. The effect of EFE addition on available methionine retention was limited. CONCLUSION: The ethanolic flaxseed extracts exhibit antioxidant activity during frozen storage of meat products. They can be utilized to prolong shelf-life of the products by protecting them against lipid oxidation and deterioration of their nutritional quality. However, antioxidant efficiency of the extracts seems to depend on chemical composition of raw material (flax variety). Further investigations should be carried on to explain the issue.

Thiamine losses during storage of pasteurised and sterilized model systems of minced chicken meat with addition of fresh and oxidized fat, and antioxidants.

BACKGROUND: The aim of the study was to determine the effect of pasteurisation and sterilization of model systems of minced chicken meat in the presence of low or high-oxidised pork lard, soy and sunflower oil, as well as casein hydrolysate and rosemary extract, on losses of thiamine in model systems. METHODS: In the samples, the thiamine content was analysed periodically by thiochromium method, as well as rate of lipid oxidation based on measurement of peroxide value (PV) by iodometric method and p-anisidine value (AV) by spectrophotometric method. RESULTS: It was observed that the thiamine losses in model systems of minced chicken after pasteurisation (61-71%) were higher than after sterilization (57-67%). Introduction of high-oxidised fat increased the total thiamine losses both during thermal processing and storage of meat samples (to 23%). A strong relationship was established between thiamine losses and rate of fat oxidation. The lowest total thiamine losses were observed in the samples with low-oxidised pork lard. Antioxidant addition (rosemary extract or casein hydrolysate) into meat samples limited the thiamine losses. However, the effect depended on oxidation of fat that was mixed with meat. In the samples with low-oxidised fat, higher protective effect was found for rosemary extract (7-11%). In the samples with high-oxidised fat, casein hydrolysate was superior to rosemary extract (14%). CONCLUSIONS: In order to increase the stability of thiamine in pasteurized or sterilized meat products with fats, the influence of fat type and its oxidative stability should be taken under consideration. Moreover, the addition of rosemary extract or casein hydrolysate has impact on the thiamine losses since it slows down lipid oxidation to a significant extent.

The effect of iodine salts on lipid oxidation and changes in nutritive value of protein in stored processed meats.

The aim was to assess the effect of iodine salts (KI or KIO(3)) on lipid oxidation as well as changes in the availability of lysine and methionine and protein digestibility in frozen-stored processed meats. Three types of iodine salt carriers were used: table salt, wheat fiber and soy protein isolate. The results showed no catalytic effect of iodine salts on lipid oxidation in stored processed meats. The application of a protein isolate and wheat fiber resulted in the inhibition of lipid oxidation in meatballs. During storage of meat products the contents of available lysine and methionine as well as protein digestibility were decreased. The utilization of wheat fiber as an iodine salt carrier had a significant effect on the reduction of lysine losses. No protective properties were found for the wheat fiber or soy protein isolate towards methionine.

The application of wheat fibre and soy isolate impregnated with iodine salts to fortify processed meats.

The aim was to use wheat dietary fibre and soy protein isolate as carriers of KI and KIO(3) for fortification of processed meat with iodine. Products from minced pork were prepared with addition of iodised wheat fibre and soy isolate, and iodised table salt for comparison and the effects of thermal processing and storage on changes in iodine content were determined. It was shown that both alternative carriers limited the iodine changes in meat products compared with iodised table salt. However, wheat fibre was more effective in limiting iodine losses during thermal processing and soy protein during storage of the products. The greatest effect of the carriers was found in meat products fortified with the less stable KI.

The application of collagen preparations as carriers of rosemary extract in the production of processed meat.

The application of collagen preparations as carriers of rosemary extract in the production of wiener-type and liver sausages has been evaluated. The rosemary extract was introduced into the meat products using one of two carriers (collagen hydrolyzate or collagen fibre preparation) or directly (i.e. using no carriers). The relationship between the methods of extract introduction and its antioxidative action was assessed on the basis of the lipid oxidation (i.e. determination of peroxide value and TBARS) during cold storage of sausages in air or in vacuum. The introduction of rosemary extract to the products via the collagen fibre preparation limited lipid oxidation greater than the direct addition of the antioxidant to both meat products, irrespective of storage. On the contrary, in the case of the application of collagen hydrolyzate as a carrier of extract, a masking effect was observed, diminishing the antioxidative impact on the tested products.