The Effect of Adding Degreased Flaxseeds on the Quality of Pates

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Introduction
Degreased flaxseeds are formed as a by-product after pressing flaxseed oil, most often utilized as animal feed [1].However it is an ingredient naturally rich in bioactive compounds such as protein (20-30%), fiber (about 30%), mucilage and lignan [2].All those substances have positive health impacts, even in treating or preventing some diseases [3].For example lignan from flaxseed reduce or lower blood glucose [4], mucilage improve gastro-intestinal health [5], whereas proteins and peptides exhibit activities potentially beneficial for human health, such as fungistatic, antihypertensive, antioxidant, and antiinflammatory activities, and prevents the occurrence of neurodegenerative diseases [6].
Currently, there is observed an increase in the interest and consumption of linseed oil, and with it the production of linseed oil, as well as the waste, which are degreased flaxseeds [1].For this reasons, degreased flaxseeds started to be also economically important ingredient using which, in addition to being in line with the hugely popular zero waste trend, increases the health value of the food.
At the moment, in the research studies the degreased flaxseeds are used in bakery and confectionery for the production of health-promoting, also gluten-free products [7], as well as in the production of food for consumers on a vegan diet, mainly as milk and egg substitutes [8].However in the available scientific research, there is insufficient information on the potential use of such an ingredient in the production of meat products.However, based on the experience of other industries, it is known that it is an ingredient that can have a strong impact on the quality of the final product, as it may change the physicochemical properties.
That is why the aim of the research was to determine the effect of the addition of defatted flaxseeds on quality pates.Six variants of baked pate were prepared i.e., control sample (without degreased flaxseeds) and five samples with different degreased flaxseeds addition: 3.0%, 6.0%, 9.0%, 12.0%, 15.0%.The quality of pates was characterized on the basis of sensory assessment and pH, water activity, water holding capacity, drip loss during refrigerated storage, color parameters and texture parameters.

Pate Preparation
In the production of pates, the meat and jowl were first cook for 1.5 h and 40 min respectively.Then, meat and jowl were ground in a laboratory grinder with a mesh diameter of 4.5 mm.The pork liver was homogenized with salt (2%).The pate batter was created in Stephan's cutter by mixing ingredients (pork shoulder 32%, hot broth 28%, jowl 20%, skin emulsion 6%, pork liver 6%, egg 4%, onion (fried) 2%, salt 1.2%, herbal pepper 0.2%, marjoram 0.2%, black pepper 0.1%, nutmeg 0.05%) and the degreased flaxseed in tested amounts were added.Batter was homogenized for 4 min, and the finished batter was put into molds and baked in two stages.They were first steamed at 90 °C and then baked at 180 °C until reaching in a thermal center temperature of 72 °C.After heat treatment, the pates were cooled and stored in a cold room for 24 h.Liver pate production was performed in five repetitions (n = 5).

Sesory Quality
The pates were subjected to sensory evaluation using the QDA method after 24 h from production.The evaluated distinguishing features were: odor, hardness and juiciness, taste and general desirability.The respondens marked the evaluation results on a 10 cm graphical scale.

Water Activity
The AQUA LAB device was used to measure water activity.The measurement temperature was 23 °C.

Water Holding Capacity
The sample of 300 mg of the ground pate was placed between glass plates, on filter paper previously conditioned with saturated KCl solution, and loaded with a 2 kg weight for 5 min.Then, using the ImageJ computer program, the leakage boundary and the area occupied by the pate were outlined.The amount of leakage was determined on the basis of the difference in the area occupied by the leakage separated from the product and the pressed product.The result was expressed in cm 2 per gram of product.

Drip Loss during Refrigerated Storage
Samples (slice with a thickness of 5 cm) for the test were vacuum-packed and three weeks stored in refrigeration conditions (4-6 °C).The amount of leakage was determined based on the difference in weight of the sample before and after cold storage.The result was expressed as a percentage.

Color Parameters
The color parameters of the pates were measured using the reflection method using a Minolta CR-200 colorimeter (Konica Minolta, Warszawa, Poland) by measuring the L*, a*, b* color components.The measurement of color was made on the cross-section of the pate.

Texture Parameters
The texture of the pates (penetration force, hardness and cohesiveness) was analyzed using the TA.XT PLUS Texture Analyzer.Samples for penetration force test were cut in the form of a 20 mm thick slice.Penetration force was measured by inserting a flat cut pin with a diameter of 10 mm into a pate sample.The maximum force needed to penetrate the pin to a depth of 10 mm was measured.The speed of the measuring head was 5 mm/s.The samples for the TPA test (parameters obtained: hardness and cohesiveness) were 20 mm cubes.The pate sample was compressed with a metal cylinder with a diameter of 50 mm while maintaining the following parameters: 25% deformation of the initial height, 5 s relaxation time between pressure measurements.The speed of the measuring head was 5 mm/s.

Statistical Analysis
The obtained results were statistically analyzed using the Statgraphics Plus 4.1 program.In order to determine the effect of the addition of degreased flaxseeds on individual parameters of the quality of baked pates, a one-way analysis of variance (ANNOVA) and detailed testing using the Tukey test were carried out, the assumed significance level was α= 0.05.

Results and Discussion
To investigate the effect of adding degreased flaxseeds to pates, a sensory analysis was performed.On the basis of the sensory analysis, it was found that the addition of degreased flaxseeds in the amount of over 6% had a significant effect on the intensity of the meat and linseed odour and taste in pates.It caused, in comparison to the control sample (without flaxseed), a decrease in the perceptibility of the odour and taste of meat and increasing the perceptibility of the odour and the taste characteristic to linen (Figure 1).What is more, the addition of degreased flaxseeds also affected the sensory assessed hardness and juiciness.The addition of degreased flaxseeds to the pate batters in the amount above 9% resulted in a significant increase in the hardness of the evaluated products.On the other hand, the juiciness was influenced by the 6% addition of flaxseeds, causing its significant reduction.These changes also had an impact on the overall desirability of the products.It was found that pates with the addition of 12 and 15% of degreased flaxseed obtained significantly lower scores than the control pates (control pate 6.5 ± 0.3, pate with the addition of 12% 4.0 ± 1.4; pate with the addition of 15% 2.8 ± 1.1).No such statistically significant differences were found at lower levels of degreased flaxseed addition.Florowski et al. [9] draw similar conclusions when examining the effect of adding flaxseeds on the quality of restructured beef steaks.The authors found that the addition of 10% flax seeds resulted in a decrease in the overall quality of the products.The influence of the addition of flaxseeds on the sensory quality of meat products was also found by Yogesh et al. (2015) [10], who assessed changes in the tested sensory characteristics with just 2.5% of the addition of flax into the model meat product.The authors found that even such small amounts of flaxseeds may cause unfavorable changes in taste in the opinion of consumers, however, in the tested pates, the addition of 3% flaxseeds was acceptable by the evaluators.
Based on the results of the physicochemical analysis, it was found that the addition of flaxseeds had no effect on the pH or water activity of the tested pates.This effect was also found by Florowski et al. [9] when adding ground flax seeds into restructured beef steaks.However, its impact on water holding capacity and drip loss during refrigerated storage was found.The addition of degreased flaxseeds in the amount of 6% and more to the batter caused a significant improvement in the water holding capacity of the product and drip loss during the refrigerated storage (Table 1).The ability to affect water binding of flaxseeds in the product is due to the presence of, among others, gelling mucilages [11] and protein [12].Based on the conducted research on the effect of the addition of degreased linseeds on the color of pates, it was found that the introduction of a larger amount of flaxseeds into the batter resulted in a decrease in the L* color parameter (brightness) of the pates (Table 2).Statistically significant differences in comparison with the control pate were found for pates 12% addition of degreased flaxseeds.It was also found that the addition of defatted flaxseeds had no significant effect on the values of the a* color parameter of the pates, but increased the value of the b* color parameter.Such an effect was observed with the lowest tested (3%) addition of seeds.The effect of the addition of flaxseed on the color of the products is described in the literature, with an indication of a statistically significant decrease in color brightness, which reflects the darker and brownish color of the flaxseed itself [1,13].In some studies, however, the authors indicate the opposite effect, that flaxseed enrichment lightened the crust of the bread, the reason of this might be connected with decreasing the availability of reducing sugars and free amino acids for the formation of Maillard reaction products, precursors to crust browning [13].
On the basis of the tests texture parameters, it was found that the introducing of a small amount of defatted flaxseeds, i.e., 3%, into the pate batter had no significant effect on any of the analyzed texture parameters (Table 3).With the addition of a larger amount of defatted flaxseeds, significant differences in the texture of pates were found compared to the control variant of the pate, including an increase in penetration power (with the addition of 15% of defatted flaxseeds), hardness (with the addition of 15% of defatted flaxseeds) and a decrease in cohesiveness (with the addition of 6% defatted flaxseeds and more).The increased hardness of pates with the addition of flaxseeds is caused by the presence of fiber and protein, which significantly affect the structure of the products [14].

Conclusions
Results of the analysis showed that degreased flaxseeds addition at a level 3% had no significant impact on most of the analyzed physico-chemical and sensory characteristics of pate.It is therefore possible to produce good quality pates with 3% of this nutritionally valuable ingredient.The main limitation in introducing higher level (especially 12-15%) of flaxseeds into the products is to deterioration of their sensory quality, mainly the decreased of the intensity of the taste and smell of the meat while increasing the intensity of the taste of the seeds.The largest tested addition of flaxseeds to the stuffing of pates resulted also in changing color parameters by lowering the lightness (L*) and increasing the yellowness (higher +b* value), as well as increasing the penetration force, hardness and lowering the cohesiveness of the products.The production of pates containing a higher amount of defatted flaxseeds requires taking measures to minimize the adverse impact of their addition on the quality of products.The positive effect of addition of degreased flaxseeds, besides adding the health value of pate, was also the improved water holding capacity and reduced mass loss during refrigerated storage.

Figure 1 .
Figure 1.Effect of the addition of degreased linseeds on sensory quality features of pates.

Table 1 .
Effect of the addition of defatted linseeds on physicochemical parameters of pates.

Table 2 .
Effect of the addition of defatted linseeds on color parameters of pates.

Table 3 .
Effect of the addition of defatted linseeds on texture parameters of pates.
b ± 0.03 Means in columns with different letter symbols differ significantly (p < 0.05).