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Browsing Scientific data by Author "Maravić, Nikola"
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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 Effect of substitution of wheat flour by sourdough and whey proteins on the properties of sponge cake(National Society of Processing and Energy in Agriculture, Novi Sad, Serbia, 2022-04-08) Tomić, Jelena; Škrobot, Dubravka; Dapčević-Hadnađev, Tamara; Maravić, Nikola; Hadnađev, MiroslavAs a result of consumer preferences, including the demand for healthier and high protein and high dietary fibre plant-based food, there is a trend towards fortifying or completely replacing refined wheat flour with whole grains or alternative ingredients. Redesign of traditional foods in order to create optimal nutritional value becomes a common practice thus offering consumers a wider and healthier choice. Incorporation of proteins and/or fibres from different sources in food formulations present one of the most used approaches. Recently, the application of sourdough technology has gained research interest due to its complexity as well as its ability to promote beneficial modifications on sensory, technological and nutritional properties of bakery products. The technological application of sourdough can offer several advantages such as improving texture and palatability of cereal based products, stabilizing or increasing levels of various bioactive compounds, retarding starch bioavailability and improving mineral bioavailability. This study aims to investigate the effects of substitution of wheat flour by sourdough from whole wheat flour (at levels 20% and 30%) and whey protein concentrate (at level 10%) on the quality of sponge cakes. The characterization of sponge cakes included the evaluation of chemical composition, specific volume, colour and texture properties. The sensory evaluation of sponge cake samples was carried out by a panel of ten trained sensory assessors who evaluated following attributes: shape irregularity, density, pores uniformity, cohesiveness, elasticity, adhesiveness, crumbliness, odour (overall intensity, on eggs), flavour (overall, on eggs), taste (sweet and bitter) and sweet aftertaste. All experimental data were subjected to one-way analysis of variance (ANOVA). To the aim, a Tukey's honestly significant difference (Tukey's HSD) test was carried out to determinate significance differences (P < 0.05) between samples. Regarding the proximate composition and colour measurements, results were, as expected, strongly dependent on the raw materials used in the formulation. Generally, the incorporation of proteins resulted in creation of product which can be labelled as protein source since more than 12% of their energy value is provided by protein. Compared to the control sample, reduction of wheat flour by sourdough and whey proteins caused a significant decrease in specific volume while values of hardness of tested samples were significantly higher. Regarding the sensory analysis, samples with sourdough and proteins exhibited much denser structure with a noticeable number of non-uniform large pores. Reduction of wheat flour by sourdough and whey proteins caused the loss of bitter taste, flavour and odour on eggs while the sweetness for these samples was significantly pronounced. The results indicate that this combination of used ingredients have a potential to be considered as an alternative valueadded food ingredients for bakery products but further research should be conducted in this area.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.