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Browsing Scientific data by Author "Jovanov, Pavle"
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Item Application of temporal dominance of sensations in sensory profiling of sourdough starter odour(National Society of Processing and Energy in Agriculture, Novi Sad, Serbia, 2022-04-08) Škrobot, Dubravka; Tomić, Jelena; Dapčević-Hadnađev, Tamara; Maravić, Nikola; Jovanov, Pavle; Hadnađev, MiroslavSourdough is one of the oldest examples of natural starters, obtained from the mixture of cereal flour and water, fermented with naturally occurring or selected lactic acid bacteria (LAB) and yeasts. Fermentation process depends on naturally occurring microbiota, type of flour, flour composition, additional ingredients, tap water, and temperature. During fermentation, acidification, proteolysis and activation of a number of enzymes, as well as the synthesis of microbial metabolites, influence not only the nutritional/functional quality of baked goods but also contribute to development of odour and flavour of starter and final product. In order to describe the evolution of the sourdough odour during starter activation, the method of temporal dominance of sensations is performed. Temporal Dominance of Sensations (TDS) is method used in sensory analysis which enables characterization of an entire profile of complex food in a short time. This approach is aimed at repeatedly recording the dominant sensations perceived during the tasting period. For the presented study experienced sensory panellists (n = 12, eight female and four male, 25 – 45 years old), used to participate in sensory profiling, were recruited. Whole grain wheat sourdough starter samples were collected and evaluated for each 1 h within six hours from the start of the sourdough activation. Samples were delivered to the panellists in a glass jars with a lid. The panellists were instructed that once they remove the lid, they have to click on the “START” button on the screen to begin the evaluation and to activate software. During an evaluation, the panellists had to select dominant odour sensation from ten simultaneously presented odour attributes (brans, flour, dough, yeast, acetic acid, lactic acid, sour milk, yoghurt, cheese, and fruity). When panellists noticed that one dominant odour perception changed, they had to score new dominant sensation. If none attribute was perceived as dominant sensation, panellists had to click the “End” button. TDS was performed for all samples within three replicate sessions by all panellists. TDS data was collected by Excel, while with XLSTAT software collected data was calculated and presented by curves showing dominance rate (Axis Y) for each 0.2 s step during the 1 min period (Axis X). TDS curves clearly showed changes in odour profile during period of sourdough starter activation. At the beginning of the activation process, flour-like, brans-like and dough-like attributes were dominant odour characteristics. However, during the time, these odour characteristics had little contribution to the overall odour profile since they became masked with more sharp odour notes reminiscent of sour milk, cheese, yoghurt and acetic acid. Over time, odour profile became more complex indicating complexity of biochemical processes.Item Impact of porridge composition on its physico-chemical properties and starch digestibility as assessed by in vitro assays(Faculty of Technology, Leskovac, Serbia, 2021-10-23) Dapčević-Hadnađev, Tamara; Šimurina, Olivera; Tomić, Jelena; Jovanov, Pavle; Hadnađev, MiroslavThe aim of this study was to design high protein and high fibre functional porridges and evaluate the effect of their nutritional properties on their performance during meal preparation as well as starch digestibility using an in vitro assay. Porridge blends were formulated using corn grits extrudates, oat flakes, oat bran, soy protein isolate, caseine and sweetening agents (xylitol, steviol glycosides and fructose) in different ratios in order to obtain high fibre porridge (HF), high protein porridge (HP) and high fibre/high protein porridge (HFP). Porridges were investigated for nutrients composition, water absorption capacity, rheological properties (flow curve and dynamic oscillatory measurements) and rate and extent of starch digestion. All porridge samples, irrespective of the fibre and protein content, exhibited shear-thinning behaviour. The apparent viscosity and a shear thinning rheological response of prepared porridges (1:2.5 porridge to boiling water ratio) have been found to be strongly dependent on their water holding capacity. Porridge characterized with high protein content (HP) has expresses the highest water holding capacity, apparent viscosity and viscoelasticity. The physicochemical properties of porridges influenced in vitro starch digestion kinetics, i.e. the reducing sugars release and diffusion through a dialysis tube which was used to simulate the barrier of the small intestine epithelium. Among all tested samples, HF porridge exhibited the lowest starch enzymic susceptibility (39% during 300 min of digestion), which could be attributed to protective properties of present dietary fibres which can reduce starch accessibility to amylolytic enzymes by adhering on the starch granules. Overall, by combining natural fibre and protein sources it is possible to create porridges with improved nutritional– physiological-processing performance.Item Kinetic of phytic acid degradation in spontaneously fermented ancient wheat sourdoughs(Cereals & Europe; International Hellenic University, 2022-04-08) Dapčević-Hadnađev, Tamara; Maravić, Nikola; Jovanov, Pavle; Hadnađev, MiroslavWhole grain flour is an important source of minerals but also contains considerable amounts of phytic acid, which is known to reduce their dietary availability. Some processing technologies, such as sourdough fermentation, influence increased phytate hydrolysis through pH lowering effect thus releasing chelated divalent cations. The aim of this study was to investigate the influence of ancient wheat variety on the phytic acid degradation during spontaneously fermented sourdough propagation with traditional backslopping procedure throughout 5 days. Spontaneously fermented emmer, spelt and khorasan sourdough was prepared through backslopping (every 24 h, 5 days) under laboratory conditions (temperature of 25 °C, dough yield of 200). Phytic acid content, as well as total and free phosphorous content, was monitored during the whole process of sourdough propagation with the aid of an enzymatic assay kit. Initial phytic acid content in emmer, spelt and khorasan wholegrain flour ranged from 1.07 to 1.13 g/100 g. Sourdough fermentation of ancient cereal flours resulted in abrupt decrease in phytate content after second backslopping step (47% to 75% of the initial content). The extent of phytate degradation was shown to be dependent from the ancient wheat variety used for spontaneously fermented sourdoughs preparation. Khorasan flour was characterized with the highest phytate reduction rate. Consequently, phosphorous bioaccessibility of all three wholegrain flours was improved due to phytate hydrolysis, as well as direct solubilisation. An increase in free phosphorous content (3.8 to 4.4 times) was detected in sourdough samples compared to respective flour samples. In general, spontaneous sourdough fermentation was proved to be an efficient processing technology for phytic acid reduction in whole grain cereal flour. The extent of phytic acid degradation was influenced with ancient wheat variety, where spontaneously fermented hulled grains' flours such as spelt and emmer performed less efficient in comparison to hull less khorasan wheat.Item Rheological performances of ancient wheat varieties(Editura Universitara, Ex Terra Aurum, Universitatea de Stiinte Agronomice si Medicina Veterinara Bucuresti, 2020-11-19) Dapčević-Hadnađev, Tamara; Tomić, Jelena; Jovanov, Pavle; Hadnađev, MiroslavAncient wheat varieties are recently gaining an interest since several studies have targeted them as healthier alternatives to modern wheats. However, impaired baking properties compared to modern varieties, constitutes a great technological challenge. Aim of this study was to conduct a comparative evaluation of the rheological properties of ancient wheat species such as emmer, spelt and khorasan varieties. In order to achieve this, the wholegrain flours of these varieties were prepared and evaluated for mixing and thermal properties using Mixolab® device. Rheological measurement have shown that spelt and emmer flour were characterized with similar rheological profiles in terms of water absorption, dough stability, dough weakening upon mixing and heating and starch pasting properties. These two flours differ only in dough development time (DDT) and elasticity, where spelt flour exhibited almost twice higher DDT than emmer flour, while emmer flour was two times more elastic than spelt flour. On the contrary, khorasan flour was characterized with two peaks during dough development, grater dough stability and higher starch gelatinization and retrogradation rate. Considering the obtained results, among the ancient wheat varieties, khorasan can be the most suitable for bread-making. In general, making bread from ancient wheats will require modified baking techniques in order to satisfy the increasing consumer demand for these products, while improving wheat genetic biodiversity.