Browsing by Subject "extrusion"

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  • Sundarrajan, Lakshminarasimhan (Helsingfors universitet, 2014)
    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.
  • Kantanen, Katja (Helsingin yliopisto, 2020)
    New alternatives for meat as the main source of protein are needed due to the negative impact of meat production on the environment and its high utilization of land sources. Vegetable proteins offer a more sustainable choice for meat and they can be processed into a structure that resembles meat using extrusion technology. The aim of this study was to produce a minced meat analogue using extrusion technology. The goal was to gain more information on the textural properties, colour and sensorial features of the meat analogue. In the experimental part, extrudates with replicates were produced from plant protein and fibre concentrate. Three differently processed samples were analysed. Texture analyser was used to measure the gumminess, springiness, chewiness, hardness, adhesiveness and shear energy of the samples. In addition, colour and moisture content were measured and a sensory experiment was conducted. According to the results, the content of the plant protein and fibre concentrate affected the textural properties and the colour of the samples. The results also showed that the composition of minced meat analogue had different effect on the textural properties depending how the sample was processed. In the sensory experiment, the reference sample (minced meat) had significantly higher score of pleasantness compared to extrudate containing samples. No significant differences were observed among the extrudate containing samples. This study showed that a product with some similarities to minced meat can be produced using extrusion technology with plant protein and fibre concentrate. For the development of the meat analogue, a more comprehensive sensory analysis would help to gain more information about the development targets of the product.
  • Turkki, Tuomas (Helsingin yliopisto, 2020)
    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.
  • Qin, Xiaoxue (Helsingin yliopisto, 2014)
    Rye bran contains dietary fiber, and lipids. Unsaturated fatty acids make rye bran products vulnerable to oxidation and formation of off-flavor. High level of dietary fiber gives rye bran a rough feel in the mouth. Therefore, extrusion was chosen to make rye bran products more appealing to consumers. The literature review covered flavor of rye, lipids in rye, lipid oxidation in cereals, extrusion of cereals, and principles of the HS-SPME-GC-MS method. The aim of this thesis was to study stability of lipids of rye bran during the extrusion process using different extrusion parameters, and the stability of extrudates during storage. Four experiments were carried out. The first three were to analyze the effect of extrusion die temperature (80, 100, 120 and 140 °C), water content of the rye bran feed (13, 16, 22, and 30%) and particle size of the rye bran (633 ± 13 and 15 ± 1 ?m). In the last experiment, five most interesting samples were selected from the previous three experiments and reproduced. A stabilization of relative humidity was conducted. HS-SPME-GC-MS analysis was run after stabilization to determine effects of the parameters on the initial quality of extrudates, and then every two weeks till the 10-week time point. In total of 88 (max.) volatile compounds were detected. Among them, 30 volatiles were selected for further study based on peak areas at first, mainly lipid oxidation and Maillard reaction products (MRPs): aldehydes, furans and pyrazines. PCAs analyzing the extrudates were run with the 30 compounds as variables. Ten volatiles appeared to have a significant effect on the PCA model. From the first experiment, extrusion temperature of extrusion die had a small effect on the oxidation stability. The indicator of oxidation, hexanal, of all samples had almost the same level at initial point (around 3.0 * 107 counts/s). The increasing tendency during storage was also similar. MRPs were more likely to appear in the extrudates produced at higher temperature (140 °C). From the second experiment, water content had great impact on the oxidation and MRPs. MRPs were better released at 2-week time point and then decomposed or reacted with other compounds. The initial state of oxidation was similar, but during the storage, the lower the water content was, the better the oxidative stability the extrudates had. Comparing the results of the experiment 2 and 3, the level of MRPs was much higher when the particle size of the bran was small, while the oxidative stability was improved in the third experiment, especially in the 16% water content samples. In conclusion, water content and particle size of rye bran had significant influence on the initial state of the extrudates. Samples produced with lower water content and bran with finer particle size had better oxidative stability and higher level of MRPs. This will be important in the developing of extruded rye bran products.
  • Oksa, Vilma (Helsingin yliopisto, 2019)
    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.
  • Ramos Diaz, Jose Martin (Helsingfors universitet, 2012)
    Malnutrition is a common problem in Peruvian highlands and in Bolivia. Amaranth, quinoa and kañiwa are pseudocereals cultivated in these areas and regarded as good sources of protein and non-saturated fatty acids. The literature review deals with the nutritional and technological properties of amaranth, quinoa and kañiwa. The aim of this investigation was to: (1) prepare gluten free corn-based extrudates containing amaranth, quinoa and kañiwa (20% of solids), (2) study the effects of independent extrusion variables on the physical properties of the extrudates and (3) evaluate lipid stability during storage by measuring hexanal production. Extrudates were made in 4 separate trials using a small scale co-rotating twin screw extruder. Experiments were performed using Box-Behnken?s experimental design in which independent extrusion variables were water content of mass (15, 17 and 19%), screw speed (200, 350 and 500 rpm) and temperature of the die (150, 160 and 170 °C). Samples were collected and their physical properties were analyzed (sectional expansion index, hardness and water content). Ground and whole extrudate samples were stored in open headspace vials at 11 and 76% RH for a week (exposure time) before being sealed and stored for 0, 2, 5 and 9 weeks at room temperature in the absence of light. Hexanal content was analyzed using headspace gas chromatography. The highest sectional expansion index (SEI) and the lowest hardness were achieved when the water content of mass was 15%, screw speed 500 rpm and temperature of the die 160 °C. Extrudates containing amaranth had the highest SEI (7.6) while extrudates containing quinoa and kañiwa had SEIs of 6.1 and 5.1, respectively. Pure corn extrudates (reference sample) had the lowest SEI (4.5). Extrudates containing kañiwa and pure corn extrudates presented the lowest (28 N/mm) and highest hardness (89 N/mm), respectively. In storage studies, ground extrudates (except samples containing quinoa) showed comparatively higher hexanal production than whole extrudates exposed to 11 and 76% RH. Whole extrudates exposed to 76% RH showed very low hexanal production during storage. This study proved that it was possible to add amaranth, quinoa and kañiwa to extruded corn snacks and achieve higher expansion than that of pure corn extrudates. Indeed, the results obtained from the evaluation of lipid oxidation during storage suggest a remarkable stability of whole extrudates after being exposed to high relative humidity. Further studies on lipid stability for longer storage would be highly desirable.