Browsing by Subject "extrusion"

Amaranth, quinoa, kañiwa and lupine are good sources of protein, fat, dietary fibre and bioactive compounds. The literature review deals with the nutritional properties and the stability of bioactive compounds and the effect of extrusion cooking on amaranth, quinoa, kañiwa and lupine. The main aim of this study was to (1) chemically characterize amaranth, quinoa, kañiwa and lupine, and (2) to determine the effect of extrusion cooking on the nutritional properties and the stability of bioactive compounds. Extrudates were processed using twin screw extruder at two different extrusion temperatures (140 and 160 °C) containing two different contents of tested flour mixtures (20 and 50%). The raw materials and the extrudates were stored at -18 °C and chemically characterized to determine fatty acid composition, tocopherol composition and total phenolic acid content. Fatty acid composition was determined using GC while tocopherol composition was detected using HPLC. The total phenolic acid content was analyzed using Folin-Ciocalteu method. The protein and dietary fibre content in lupine accounted for 29 and 50 g/100 g d.m., respectively. The extrudates containing 50% lupine and processed at 140 °C possessed higher content of oleic, linoleic and linolenic fatty acids. At higher content of tested flours, extrusion cooking at 160 °C resulted in better retention of unsaturated fatty acids in the extrudates of amaranth, kañiwa and quinoa. Higher extrusion temperatures resulted in lower retention of tocopherols in all the extrudates. The total phenolic acid resulted in higher contents in the extrudates of kañiwa when compared to other extrudates. At higher seed contents of tested flours (%), higher retention of total phenolic acid was achieved during extrusion cooking at 140 °C in the extrudates of amaranth, quinoa and kañiwa. This study showed that extrusion conditions could be optimized in order to obtain lesser effects on the nutritional properties and better retention of bioactive compounds. The research study provides supportive information for obtaining gluten-free cereal snack products with lower glycemic index.

Constant increase in protein consumption is global trend and can be seen in consumer behavior of Finnish markets. Consumers are interested in replacing meat proteins with plant proteins, and therefore, it is important to develop locally grown-domestic products and invest in local crop research. Due to this, the current study focuses on the domestic vegetable protein (faba bean and oat) texturing by extrusion cooking and on their functionality when included in burgers. The literature section presents an overview of previous studies on extrusion of vegetable proteins and the functionality of textured vegetable proteins (TVP). In the experimental work the research materials were faba bean protein concentrate and oat concentrate with high β-glucan content. The flour concentrates were texturized with high-moisture extrusion, in different mixtures. Mixtures were prepared in the ratio of: 3:1 (FO) and 1:3 (OF) and soy protein concentrate (S) was used as a reference sample. Moisture content and water absorption capability of TVP samples were measured instrumentally. TVPs were later on applied to develop burgers based on a mixture of meat and vegetable sources. Burgers were prepared for instrumental analysis with seven different recipes, where TVP inclusion, water addition and meat content varied. TVP was included in three different percentages: 0, 25 and 50% and water was added in 0, 12.5 and 25%. In relation to TVP inclusion and water addition, the meat content varied between 25-100%. Sample with 100% meat was used as control sample (0-sample) and burgers with S inclusion as reference samples. Samples were analyzed for cooking loss, shear force and texture profile (hardness, fracturability, springi-ness, cohesiveness, gumminess, chewiness and resilience) which was measured with a compression method. Based on the results of the instrumental analysis, five different burger samples were selected and evaluated for sensorial properties (chewiness, biting force, juiciness and pasty mouthfeel). The highest TVP moisture content was in OF and lowest in FO, hence the difference between S and FO was not significant. The highest water absorption was in S and lowest in OF. 25% TVP inclusion in burgers reduced the cooking loss (p<0.05) and 50% inclusion reduced it even more (p<0.05). With 25% TVP inclusion S had higher (p<0.05) cooking loss compared to FO and OF. With 50% TVP inclusion the difference was eliminated. Water addition increased cooking loss significantly (p<0.05) with each type of TVP. The FO and OF inclusion showed to weaken (p<0.05) the textural properties of burgers and reduced (p<0.05) the shear force. The reference sample S was found to maintain the structure similar as from the meat control sample. Water addition, while replacing meat, weakened also the textural properties and shear force in each TVP included sample. Based on the results, the inclusion of FO and OF in burgers reduces the cooking loss compared to the 0-sample and the reference sample S. The texture of burgers became weaker with FO and OF inclusion, however sensory evaluation revealed them to be similar to S included sample. Therefore additional studies focusing on improving the textural properties of these TVPs are needed. Faba bean and oat concentrates with higher protein contents could be needed to obtain a texture closer to meat.

Oats and peas have good nutritional composition and they could make up a favourable raw material combination for extruded food products. However, there are only few studies on their suitability for dry extrusion, especially for textured vegetable protein products (TVP). Based on protein content, dry extrudates can be divided into TVP products having fibrous structure (> 30% protein) and snack products having puffed structure (< 30 % protein). Differences in the structures of extrudates are formed as a result of the raw materials and extrusion parameters. The structure is formed in the extruder chamber, where different unit operations (for example mixing, ripening and shaping) cause many physicochemical changes in the raw materials, such as gelation of starch, denaturation and rearrangement of proteins in flow direction. The aim of the study was to find out how different extrusion parameters, oat raw materials and them concentration affect the properties of TVP products. Oat-based TVP products were targeted to have fibrous structure and resistance for soaking. In the first step, four oat raw materials in three different concentrations (25 %, 30 % and 35 %) were extruded with pea protein isolate. Moisture content, expansion, bulk density, water binding capacity, hardness and chewiness were determined from the products and a soup test simulating cooking was performed. The nutritional contents were calculated based on information received from raw material manufacturers. Based on the analysis results, the best of the oat raw materials (oat protein flour) was chosen for the second stage of the experiments. In the second stage, oat protein flour concentrations of 40%, 50% and 60% of the dry matter were tested. The extrudates were subjected to the same analyses as before. The oat raw material and its concentration were found to have statistically significant effects on many product properties, such as expansion and hardness. The best oat raw material was oat protein flour, from which the extruded products formed a fibrous and soaking-resistant structure. Increasing the oat content of the pulp in the case of oat protein flour resulted in a harder product and the expansion and water binding capacity decreased. Increasing the screw rotation speed was found to increase as well as expansion and water binding capacity. Based on the analyses and sensory observations, it was not possible to decide on the best extrudate, because the evaluation was most influenced by the evaluator's preference questions about for example meat structure. Based on this research, by combining oats and peas it is possible to obtain well-structured TVP products with a concentration of up to 60 % oat protein flour. It may be possible to increase the oat content of the extrudates by combining many oats raw materials, but at the same time it is necessary to ensure that the other properties of the extrudates are preserved.

Abstract Licorice is traditionally made from sugar, molasses, water, wheat flour, and licorice extract. In the literature review, the focus was on the properties of quinoa, licorice extrusion, sensory and physical properties of licorice and the basis behind sensory evaluation and instrumental testing in product development. In the experimental part, gluten-free quinoa and rice licorice were made and their properties were studied with multiple sensory and instrumental measurements, and the self-made samples were also compared to commercial samples to see the possible differences between them. The hypothesis was that the changes in the recipes and process parameters would result in significant differences between the products. The sensory evaluations included a generic descriptive analysis with the first batch and two separate consumer tests with the two batches. The instrumental testing conducted of compression and extension tests with Instron and the determination of water activity. The data were analyzed with one- and three-way analyses of variance, as well as principal component analysis for the descriptive analysis. The manufacturing of the quinoa and rice licorice with the twin-screw extrusion was achieved. The generic descriptive analysis revealed that all the self-made samples were described similarly to each other, while the commercial gluten-free samples differed significantly from these. The quinoa licorice was seen sticky and not homogenous in appearance or texture, while the commercial samples were described as more homogenous and more intense in their taste. The consumer tests showed that both panels preferred the commercial samples over the self-made ones and that the quinoa licorice was preferred over the rice licorice. Commercial samples were seen as soft and chewy, while all the self-made samples from both tests were described as hard and grainy. The hypothesis was overruled since the quinoa licorice samples did not have significantly different properties despite the variation in the process parameters and ingredients. The study revealed that at least with these parameters there are no noticeable, significant differences in the sensory or physical properties of quinoa licorice. The commercial samples, however, remain significantly different from the self-made samples.