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A method based on the reverse breakage matrix approach is proposed for controlling the effects that milling has on the particle size distribution and composition of the comminuted material. Applicability, possibilities, and limitations of the proposed method are tested on examples related to the process of wheat flour milling. It has been shown that the reverse matrix approach can be successfully used for defining the particle size distribution of the input material leading to the desired, predetermined particle size and compositional distribution in the output material. Moreover, we have illustrated that it is possible to simultaneously control both, input and output particle size distribution, together with the composition of the output material.

The goal of this study was application of conventional [Soxhlet (SOX)] versus novel [supercritical fluid (SFE), microwave-assisted (MAE) and ultrasound-assisted (UAE)] extraction techniques for whe...

White chocolate is considered an unhealthier product than dark and milk chocolate due to the absence of cocoa solids containing polyphenols and other valuable components such as minerals and dietary fiber. This paper aimed to improve the nutritional value of white chocolate (C) by adding blueberry bioactive compounds. Since natural polyphenols are easily degradable because of their sensitivity, whey, as a rich source of proteins, was used as a material for encapsulating blueberry juice. Whey proteins protect blueberry anthocyanins and increase their bioaccessibility in the human body. Blueberry juice encapsulates (B) were added to white chocolate, replacing 8% (C-B8) and 10% (C-B10) of white chocolate mass. Blueberry encapsulates significantly (p < 0.05) increased the viscosity of chocolates (from 0.63 Pa·s in C to 1.13 Pa·s in C-B8 and 1.40 Pa·s in C-B10) with no significant impact on their melting peak. Both enriched chocolates had significantly (p < 0.05) higher protein and dietary fiber content and lower fat content than white chocolate. The total polyphenol content increased 3.7-fold, while antioxidant capacity increased 5.2-fold in C-B10. The oxidation stability, determined by pressurized accelerated oxidation, was also improved in enriched chocolates. Blueberry juice encapsulated in whey positively influenced the color and sensory characteristics of fortified white chocolates, where C-B10 had higher sensory scores for blueberry odor and taste than C-B8. The obtained results open up a possible pathway and indicate opportunities and limitations for the incorporation of other materials, such as various dietary/fruit components, in white chocolate.

In this study, dry fractionation process was proposed in order to obtain protein-enriched sunflower meal fractions. The process includes two-stage grinding using a hammer mill and a roll mill, and fractionation of sunflower meal by sieving. Central composite design (CCD) with four variables on three levels within response surface methodology was applied in order to estimate the influence of grinding parameters (sieve openings diameter of the hammer mill: 2, 4, and 6 mm, roll gap: 0.15, 0.2, and 0.25 mm, feed rate: 0.1, 0.175, and 0.25 kg/cm min, and roll speed: 400, 500, and 600 rpm) on responses (protein content, fraction yield and grinding energy consumption). Sieve openings diameter expressed the highest impact on fraction yield while roll gap expressed the most dominant influence on protein content in the fraction and grinding energy consumption. The highest protein content obtained was 48.06%(dm) with fraction yield of 77.22%. A multi-response optimization procedure was performed and optimal values were: sieve openings diameter of 2 mm, roll gap of 0.25 mm, feed rate of 0.2 kg/cm min, and roll speed of 400 rpm, while predicted values for a desired range of responses were: protein content 45.5%(dm), fraction yield 77.89%, and grinding energy consumption 8.31 Wh/kg.

Sunflower meal, a by-product of oil extraction from sunflower seeds, is an important protein source in domestic as well as European feed industry. There is a common interest for the proper utilization of sunflower meal and for the development of an effective fractionation process in order to obtain a nutritionally improved sunflower meal. This paper proposes and compares two dry fractionation processes for the improvement of sunflower meal protein content on a laboratory scale. The first phase of both processes included two step milling using a hammer and roller mill. In the second phase, the ground sunflower meal was fractionated by sieving or by air classification. Results indicated that the implementation of any of the suggested processes improved protein content of the starting sunflower meal to a level sufficient to categorize it as "high-protein" according to current national regulation on animal feed quality, with the fraction yields over 50%. For the air classification process the most promising result was achieved for air flow of 7 m3 /h (12.8% relative protein enrichment, 56.42% fraction yield). For the fractionation process with sieving as a separation step, when fractions smaller than 350 µm were conjoined, relative protein enrichment of 28.5% and fraction yield of 51.17% were achieved. The high protein content (48.81% on dry basis) of the joined fraction enables enough space for optimizing the protein content - fraction yield ratio of obtained sunflower meal. By applying sieves with larger aperture, it is possible to obtain higher yields of sunflower meal categorized as high-protein on account of a slight decrease in protein content, which gives this process a certain flexibility and potential for application on a larger scale.

Optimization of bread dough formulation with defatted wheat germ (DWG) in terms of dough rheological properties was the objective of this study. Fractional factorial design [Formula: see text] was applied in order to investigate influence of DWG granulation (

Emergence of cultivated cereals and consequently milling of cereals is essentially connected with the beginning and development of human civilization. It is almost impossible to imagine a human nutrition without cereals. Flour milling is considered by many to be the man oldest continuously practiced industry. The evolution of milling process was slow and gradual, from early beginnings at the dawn of civilization up to today’s fully automated and computerized process. Flour milling was and still is deeply connected with many spheres of human life both socio-political and technical-technological. The following chapter aims to provide a relatively brief overview of the evolution of milling process by pointing out the most significant steps which led to the modern approach in flour milling technology.

Sugar beet pulp (SBP) is a by-product of the sugar industry in which the dietary fiber content ranges from 73% to 80%. Compared to cereal fibers mainly used in biscuit production, sugar beet fibers are gluten free and have a perfect ratio of 2/3 insoluble fiber. In this work, sugar beet pulp was extruded with corn grits (ratios of corn grits to sugar beet pulp in extrudates were 85:15, 70:30, and 55:45), and the obtained sugar beet pulp extrudates (SBPEs) were used for improving the nutritional quality of cookies. The wheat flour in cookies was replaced with SBPEs in the amount of 5, 10, and 15%. The influence of three factors (the percentage of sugar beet pulp in the SBPEs, the size of the SBPE particles, and the percentage of wheat flour substituted with SBPEs) and their interactions on the nutritional quality of cookies, as well as their physical and sensory characteristics are examined using the Box–Behnken experimental design. The addition of extruded sugar beet pulp (SBPEs) significantly increased the amount of total dietary fiber and mineral matter of cookies. On the whole, the addition of SBPEs increased cookie hardness, but the hardness decreased with an increase in extrudate particle size. Sensory characteristics (except for the taste) were the most influenced by extrudate particle size.

Influence of the milling parameters on the reduction process of the wheat middlings by the smooth rolls was investigated. Three level and four variables Box–Behnken experimental design with response surface methodology was applied in order to evaluate effects of milling parameters and to optimize grinding conditions for various responses. As independent variables roll gap (0.04–0.1 mm), differential (1.1.–1.9), roll speed (300–500 rpm) and feed rate (0.2–0.4 kg/cm min) were employed. Responsive variables were flour yield, ash content and energy consumption. In order to optimize milling process adequate models were obtained by regression analysis. Possibilities of the optimization of the milling parameters in order to obtain different combination of the desired outputs are illustrated by four examples.

White chocolate does not contain fat-free cocoa solids and thus lacks bioactive components. In the present study, white chocolate was enriched with encapsulated blackberry juice in concentrations: 60 g kg−1, 80 g kg−1, and 100 g kg−1. The results showed an increase of volume weighted mean in enriched chocolates with increasing the concentration of encapsulate from 13.06 μm in white chocolate to 18.05 μm in chocolate with 100 g kg−1 of encapsulate. Casson viscosity of chocolate mass increased at the same time (from 0.63 Pa in white chocolate to 1.22 Pa in chocolate with a maximum concentration of encapsulate) due to an increase of specific surfaces of solid particles in chocolate. Internal structure and surface gloss in chocolate with 100 g kg−1 of encapsulate are also affected where the lack of free fat phase caused mat color on the surface. However, the addition of encapsulated blackberry juice to white chocolate led to the creation of new type of enriched chocolate with attractive color and blackberry taste. Total polyphenol content (mg GAE/100 g) of white chocolate is increased from 40.75 to 75.06, 145.86, and 153.95 in chocolates with 60 g kg−1, 80 g kg−1, and 100 g kg−1 of encapsulate, respectively.

The introduction of agro-food industry by-products rich in bioactive compounds represents major challenge in food industry sector. The influence of wheat germ particle size (

peer-reviewed, In this study, sunflower meal is ground by a hammer mill after which air zigzag gravitational air classifieris used for separating sunflower hulls from the kernels in order to obtain protein rich fractions. Three hammer mill sieves with sieve openings diameter of 3, 2 and 1 mm were used, while three air flows (5, 8.7 and 12.5 m3/h) and three feed rates (30%, 60% an 90% of bowl feeder oscillation maximum rate) were varied during air classification process. For describing the effects of the test variables on the observed responses Principal Component Analysis, Standard Score analysis and Response Surface Methodology were used. Beside experimental investigations, CFD model was used for numerical optimization of sunflower meal air classification process. Air classification of hammer milled sunflower meal resulted in coarse fractions enriched in protein content. The decrease in sieve openings diameter of the hammer mill sieve increased protein content incoarse fractions of sunflower meal obtained at same air flow, and at the same time decreased matchingfraction yield. Increase in air flow lead to the increase in protein content along the same hammer mill sieve. Standard score analysis showed that optimum values for protein content and ratio of coarse and fine fractions have been obtained by using a sieve with 1 mm opening diameter, air flow of 12.5 m3/hand 60% of the maximum feeder rate. Fraction ratio and protein content were mostly affected by the linear term of air flow and the sieve openings diameter of the hammer mill sieve in the Second Order Polynomial model. The main focus of CFD analysis was on the particle simulation and the evaluation of the separation efficiency of the zigzag classifier., This work is a part of Integrated and Interdisciplinary Research Project No III 46012, funded by the Ministry of Education, Science and Technological Development of the Republic of Serbia.

Brewer's spent grain (BSG) is a by-product generated during the brewing process. It is a rich source of dietary fibre and proteins, with great potential to increase nutritional value of food products. In this research different quantities of fresh (non-dried and non-milled) brewer's spent grain (15, 25 and 50%) were added to wheat flour on a replacement basis in order to evaluate its effect on fibre and protein content, instrumental parameters of colour, microbial stability and sensory characteristics of cookies. Protein and fibre content of cookies increased following the addition of BSG from 7.55% to 9.69% and 6.8 to 15.55%, respectively. Considering the colour characteristics, addition of BSG decreased L*and b* values, while a*values increased. Enterobacteriaceae, Escherichia coli, Clostridium spp., yeasts and moulds were not detected in cookie samples, while the Enterobacteriaceae were detected (40 cfu/g) in fresh BSG. The addition of 25% of BSG resulted in best sensory characteristics of cookies in terms of surface appearance, hardness, grittiness and flavour. The results have shown that fresh BSG has a potential to increase nutritional value of the cookies without negative influence on cookie sensory characteristics and microbiological stability.

Waffles, cookies, and crackers are considered to be one of the most often consumed confectionery products. Their complex composition in terms of raw materials used for their production often implies more than one source of heavy metals that end up in the final product. Therefore, the analysis of the heavy metals in these types of products is necessary. The present study deals with the determination of the correlations between the content of essential metals with potential toxic effects (copper, iron, zinc, manganese, and cobalt) determined by inductively coupled plasma‐atomic emission spectrometry in waffles, cookies, and crackers collected from the market in Autonomous Province of Vojvodina, Republic of Serbia. The concentrations determined were in the following ranges: Cu (0.299–0.5015 mg/kg d.w.), Fe (3.301–65.35 mg/kg d.w.), Zn (1.962–15.58 mg/kg d.w.), Mn (1.406–27.7 mg/kg d.w.), and Co (0.01–0.26 mg/kg d.w.). The mutual dependence of their concentrations was determined by chemometric linear and nonlinear regression methods which showed to be useful in the fast and easy determination of iron, manganese, zinc, and cobalt concentrations in the studied groups of confectionery products. PRACTICAL APPLICATIONS: The practical application of the established chemometric models is reflected in the possibility of predicting the concentration of one metal in waffles, cookies, and crackers based on the concentration of the other one. In this way, the additional experiments can be avoided and the concentration of particular metal can be precisely determined, which is confirmed by the internal and external statistical validation procedures of the established chemometric models.

The aim of this study was the optimization of supercritical fluid extraction (SFE) of wheat germ oil obtained as by‐product from industrial mill. Extraction kinetics modeling and response surface methodology (RSM) were used for that purpose. SFE was performed with broadening Box‐Behnken experimental design, where pressure (250–350 bar), temperature (40–60°C), and CO₂ flow rate (0.2–0.4 kg/hr) were used as independent variables. Five empirical kinetic equations were successfully utilized for modeling of SFE. Model IV (Kandiah and Spiro model) provided the best fit with experimental data, according to statistical parameters (R², sum of squared errors and average absolute relative deviation). Furthermore, initial slope calculated from this model was used as a response variable for RSM optimization. It could be concluded that SFE should be performed at elevated pressure (350 bar) and CO₂ flow rate (0.4 kg/hr), while temperature should be held at a lower level (40°C) in order to achieve a maximal initial slope. PRACTICAL APPLICATIONS: Optimization and modeling of industrial processes are crucial factors that will determine its efficiency and profitability. This research provided information about modeling of green and environmentally friendly extraction technique, that is, SFE, which could be successfully utilized for recovery of valuable oil from food industry by‐product, that is, wheat germ. Commonly used empirical models were successfully applied for modeling of extraction process and influence of SFE factors on model parameters was determined providing information about mass transfer phenomena during extraction. Further investigation provided determination of the highest initial extraction rate constant which could be applicable for optimization of industrial scale processes.

Background Many studies have described cocoa polyphenols as being bioactive compounds with a potential positive effect on human health. Although dark chocolate is a most powerful source of antioxidants, their content is lower in milk chocolate; conversely, in white chocolate the fat-free cocoa solids are omitted. The aim of this study was to increase polyphenol content and antioxidant capacity of white chocolate by adding encapsulated green tea extract (GTE) in amounts of 60, 80 and 100 g kg-1 . Results GTE influenced the particle size parameters, increasing the volume weighted mean from 15.43 μm in white chocolate to 19.34 μm in chocolate with 100 g kg-1 GTE. At the same time, the viscosity of enriched chocolate also increased owing to the addition of new solid particles. The surface color of enriched chocolates changed in accordance with the amount of encapsulate, where all enriched chocolates had a slightly lighter color after 12 months of storage. Total polyphenol content (mg gallic acid equivalents (GAE) kg-1 ) increased from 0.41 in white chocolate to 2.73 in chocolate enriched with maximal GTE. This amount of GTE increased antioxidant capacity (mmol Trolox equivalents kg-1 ) from 1.22 in white chocolate to 16.12. After 12 months of storage, degradation of polyphenols was found to be a maximum of 37.27%, while antioxidant capacity decreased up to 44.14%. Conclusion In addition to the impact on chocolate viscosity, GTE added value through the polyphenol content and sensorial profile of the new product with an unusual green tea flavor and a shelf life of at least 12 months. © 2019 Society of Chemical Industry.

The main raw material for cookies production is wheat flour (white or wholemeal/integral) as a nutritionally highly valuable component. In addition to the benefits it brings, this raw material is also a potential source of contamination with residues of heavy metals originating from soil and plant protection agents. Therefore, it is necessary to analyze their concentrations in both wheat flour and final products, since the wheat flour is often present in cookies and related confectionery products in a proportion >60 or 70%. The aim of this paper was to determine the content of heavy metals, including highly toxic ones (As, Cd, Hg and Pb) and essential metals with potential toxic effects (Fe, Cu, Cr, Co, Mn, Ni, Zn) in cookies, waffles and crackers available in local markets in the Autonomous Province of Vojvodina, Republic of Serbia. The present study is focused on chemometric estimation of the risk group of confectionery products containing wheat flour in an easy and efficient way. Hierarchical cluster analysis, principal component analysis, linear discriminant analysis and the sum of ranking differences analysis were applied for this purpose as chemometric tools with substantially different theoretical bases. The obtained results indicated that there is a specific group of cookies with a relatively high content of heavy metals. The group of crackers contained lower concentrations of heavy metals than the other groups of studied products. The results of the sum of ranking differences analysis indicate that there is no strict separation between the samples regarding the ratio among heavy metals contents.

Chocolate contains a variety of different compounds such as fats, carbohydrates, proteins, vitamins, and minerals. Fat-free cocoa particles are also extremely rich in polyphenols. While dark chocolate is a most powerful source of antioxidants, the content of these components decreases with the reduction in the content of dark cocoa particles in chocolate. White chocolate differs from milk and dark through the absence of fat-free cocoa particles containing antioxidants. Today's investigations are focused on finding new methods of creating functional confectionery products. Accordingly, in this study white chocolate was enriched with100 g kg-1 of encapsulated black tea extract in order to increase its polyphenol content. The addition of encapsulated black tea extract to white chocolate increased the viscosity of enriched chocolate mass to the extent that is acceptable for the production of this kind of product. Total polyphenol content in enriched chocolate was increased over 6 times compared to white chocolate. However, black tea encapsulate contributed to foreign taste of medications in enriched chocolate, making it unacceptable by consumers.

Besides pleasant taste, the potential health benefits of cocoa and chocolate products have been known for many years. Formerly accepted as a medicine, chocolate nowadays among consumers represents everyday delicacy primarily associated with caries, obesity, high blood pressure, and diabetes. However, recent studies indicate the potential role of chocolate in cardiovascular diseases prevention and benefits linked to lower body mass index (BMI). The presented study aims to examine adolescents’ habits regarding chocolate, sweets, salty snacks and fast food consumption as well as corresponding products intake frequency and relate them with BMI. The study population encompassed 525 participants attending elementary and high schools in the province of Vojvodina, Serbia, from which 42.5% were boys and 57.5% girls. The risk for overweight and participants’ nutritional status were determined through BMI assessment. The majority of participants had normal range nutritional status (70.5%) followed by overweight (19.8%) and obese (7.6%). Increased number of overweight and obese nutritional statuses was recorded among boys compared to girls. Results revealed that fruits as a snack are most frequently consumed between meals, followed by salty snacks and sweets, regardless of the participants’ nutritional status. The highest share of sweets consumption between meals was noticed among participants with obese nutritional status (15%). Furthermore, more than 40% of participants with overweight and normal range nutritional status do not consume chocolate at all, while 2.5% of participants with obese nutritional status stated that they consume chocolate on a daily basis.

The breakage matrix approach is a mathematical tool to relate input and output particle size distribution from a milling operation. Adjustment of the break release in the flour milling process is extremely important because it affects granulation and quality characteristics of the stock and hence the total results and balance of the mill. In this study the breakage matrix approach has been used for the purpose of controlling the release on the front passages of the break system in the flour milling process.; Results: It has been established that, for any particle size distribution of wheat, it is possible to predict break releases together with the distribution of the release size fractions by using the breakage matrices. Also, the reversibility of this approach is examined, that is the possibility to identify the wheat particle size distribution that would result in desired break releases and/or the desired yields of different sized intermediate stocks under the given set of milling conditions.; Conclusion: It is confirmed that the breakage matrix approach can be successfully used to predict the break releases. The reverse breakage matrix concept allows the determination of the wheat particle size distribution which would result in a targeted break release. © 2016 Society of Chemical Industry.; © 2016 Society of Chemical Industry.

peer-reviewed, In recent years there is an emerging trend of coarse grinding of cereals in production of poultry feed due to the positive influence of coarse particles on poultry digestive system. Influence of grinding method (hammer mill vs. roller mill) and grinding intensity of corn (coarseness of grinding) on mill specific energy consumption and pellet quality was investigated. By decreasing grinding intensity of corn (coarser grinding), specific energy consumption of both hammer mill and roller mill was significantly decreased (p < 0.05). When comparing similar grinding intensities on hammer mill and roller mill (similar geometric mean diameter or similar particle size distribution), specific energy consumption was higher for the hammer mill. Pellet quality decreased with coarser grinding on hammer mill but, however, this effect was not observed for the roller mill. Generally, pellet quality was better when roller mill was used. It can be concluded that significant energy savings could be achieved by coarser grinding of corn before pelleting and by using roller mill instead of hammer mill. From the aspect of pellet quality, if coarser grinding is applied it is better to use roller mill, concerning that more uniform particle size distribution of corn ground on roller mill probably results in more uniform particle size distribution in pellets and this provides better pellet quality., Authors would like to express their gratitude to Serbian Ministry of Education, Science and Technological Development who supported this work as a part of Project No III 46012. Authors would also like to thank to Province Secretariat of Science and Technological Development of Autonomous Province of Vojvodina for financial support.

The Box–Behnken experimental design and modern instrumental methods were applied to examine the rheological and textural characteristics of the cookie dough, depending on the amount of flour replaced with wheat germ (5, 10 and 15%), different particle sizes of wheat germ (

Consumers are becoming aware of health benefits of dietary fiber intake. In past years, the development of products containing different fiber is increasing. The aim of this research was to look into the effect of addition pea fiber to dough for crackers. Rheological and textural properties were evaluated. In order to develop dough in which wheat flour was partly substituted with pea fiber, it was necessary to increase water content. The addition of 5% and 10% of pea fiber affected intramolecular linkages of gluten and lowered elastic properties of the dough. Dough with addition of 30% of fiber was brittle, grainy and impossible to process.

Double grinding of mill streams without intermediate sieving, i.e. the eight-roller milling system provides opportunities for significant reduction of capital cost compared to conventional wheat flour milling system. In this study the effects of using the eight-roller mill in the purifier-less mill flow were investigated. Middlings from the break system of commercial flour mill, which would be sent to the purification system, were intercepted and employed in the experiments. Milling results obtained with double grinding of middlings were compared with the results obtained by conventional system with intermediate sifting before regrinding of stock. At the same roll gap setting and under the same sieving conditions, the eight-roller system produced less flour compared to the conventional system. Results showed that the most efficient way to increase flour yield in the eight-roller milling system is to increase the upper size limit of flour by increasing the sieve aperture. This is not followed by the deterioration of flour quality as determined by ash content. Increase of the upper size limit of flour particles is followed by the decrease of the flour ash content suggesting that it is possible to implement the eight-roller mills in the purifier-less mill flow.

This paper is a complete overview of the reverse problem in the breakage matrix context. The procedure for calculating the input particle size distribution to a milling operation in order to obtain the desired output particle size distribution is given. The reverse problem was solved by the “precision” and “approximation” approaches. For the precision case, a detailed algorithm is presented, where in every step a precise range for the current output is provided. This approach is limited with a number of output size fractions that can be freely chosen. On the other hand, the approximation approach gives the best-fit solution which corresponds to the desired output particle size distribution. In this case the problem is solved by the orthogonal decomposition and non-negative least squares method and by semilogarithmic loss function. Applicability of the proposed methods was confirmed by examples related to wheat milling.

peer-reviewed, The aim of this study was to determine the effect of the main milling variables, i.e., agitator shaft speed (50, 75 and 100%, which is 25, 37.5 and 50 rpm) and milling time (30, 45 and 60 min) on physical and sensory properties of fat filling, as well as on energy consumption during the production in a laboratory ball mill. Within the response surface method, the face centered central composite design is used. A response surface regression analysis for responses was performed and a full quadratic model was fitted to the experimental data. It is shown that agitator shaft speed had the most significant influence on physical properties (particle size distribution, rheological and textural propertes) and sensory characteristics of fat filling, while the milling energy consumption is highly influenced by milling time with contribution 55.4%, followed by agitator shaft speed (40.04%). The model obtained by regression analyses was used to perform the optimization of processing parameters in order to provide the combination of agitator shaft speed and milling time that cost less energy while at the same time do not compromise the quality of the fat filling. Optimization of production of fat filling in a laboratory ball mill would imply the maximum agitator shaft speed and 30-min milling time.

Roller mills are one of the most frequently used grinding machines especially for cereal milling. Magnitude and type of the forces acting on particle depend on the set of roll parameters. Particle size distribution (PSD) resulting from milling a particular feed size critically depends on the ratio of roll-gap to input particle size. Box-Behnken experimental design was applied in order to optimize roll-gap adjustments and desired PSD of the milling output obtained by subsequent grinding of wheat on three pair of rollers. Adequate models, which allow the optimization of the milling process, were obtained by regression analysis. Values that define the PSD of the output, i.e. weight fractions of the milling output size fractions, were set to minimum, maximum or values within a certain interval. The examples of optimization which set the roll-gap values to ensure the desired PSD of the output, were obtained with a high level of desirability.

A challenge for food producers is certainly to find suitable flour that can replace wheat flour in the production of flour–based products. Chestnut flour can be adequate substitute for wheat flour in the production of gluten–free flour confectionary products, due to high starch and sugar content. The objective of this work was to characterize physical changes, rheological and textural properties of dough for cookies with chestnut flour. The control dough was only with wheat flour. The substitution of wheat flour with chestnut flour for examined dough samples was at three different levels (20, 40 and 60%). Moisture of the dough was 22%.Dynamic oscillatory measurements describe all dough samples as typical viscoelastic systems with dominant elastic modulus G' over viscous modulus G". The modulus ratio (tan δ=G"/G') decreased with increase in amount of chestnut flour. Also, the dough compliance (J) determined by creep and recovery curves decreased, thus more chestnut flour resulted in more brittle consistency of the dough. Texture determination confirmed the rheological results. Resistance to extension of the control dough sample was the highest, as well as dough extensibility. Application of chestnut flour and increase in its amount reduced these texture parameters for dough samples. Optimal physical properties of dough were achieved with low amounts of chestnut flour of 20%.

Wheat germ was firstly defatted using supercritical CO2 extraction and raffinate was further utilized for polyphenols isolation. For that purpose solid-liquid, ultrasound-assisted and microwave-assisted extraction (MAE) techniques were applied. MAEs were performed at different levels of ethanol concentrations, extraction time, liquid-solid ratio and irradiation power, while ethanol concentration was only variable for other extraction techniques. Obtained extracts were evaluated in terms of total extraction yield, total phenols yield and in vitro antioxidant activity, whereas under certain conditions MAE exhibited the highest response values. MAE was analyzed by response surface methodology (RSM) and artificial neural network (ANN) techniques which were compared in terms of fitting quality, influence analysis and optimization. Results indicated that RSM and ANN could be successfully used to describe experimental data. Both methods exhibited certain advantages, i.e. ANN showed minor advantage of fitting quality, while RSM provided further insight in influence analysis. Optimized MAE conditions determined by RSM were ethanol concentration of 58.03%, extraction time of 14.48 min, liquid-solid ratio of 25 mL/g and irradiation power of 800 W. MAE conditions optimized by ANN were different in terms of ethanol concentration (50%), extraction time (15 min) and irradiation power (400 W), and same in terms of liquid-solid ratio.

The breakage matrix approach proved to be a useful tool in describing the milling processes. Having determined the breakage matrix for any particle size distribution (PSD) of input material, the PSD of output can be predicted. In this paper, the reversibility of the aforementioned approach is examined. Perceived limitations of the breakage matrix approach are considered within the mathematical calculation. It is established that the procedure is determined by the dimension of the breakage matrix (relation between the number of input and output size fractions). The paper shows that the breakage matrix approach can be used to define the PSD of the input material to a milling operation which would give the desired PSD of the output material.

Five statistical procedures including: simple correlation, multiple linear regression, cluster analysis, factor analysis and principal components analysis were used to study the influence of wheat/flour quality tests on end-use performance. Different statistical procedures identify different quality test to be in good correlation with bread yield and specific bread volume confirming the complexity of wheat quality determination. Factor analysis and principal components analysis identified three group of parameters named: protein quantity and quality, extensigraph readings and alpha-amylase activity which explain 73.6% (factor analysis) and 82.54% (PCA) of the total variability in the dependent structure.

The work is concerned with the effects of applying the drum detachers as flake disrupters in industrial wheat flour mills. The stocks entering and leaving the drum detachers applied on the different reduction passages in two industrial mills were intercepted and employed in the experiments. The changes in the flour release and flour ash content were followed. The results show that the drum detachers are effective in disrupting the flakes formed in the smooth roller mills grinding zone. However, the contribution of the drum detachers to the overall milling efficiency is in close correlation with the nature of the formed flakes. If the flakes are primarily composed of endosperm particles, the employment of drum detacher results in a statistically significant increase of the flour yields without deterioration of flour quality. If flakes, formed on the end passages of the reduction system, contain large portion of branny particles, the increase of the flour ash content following the drum detacher is statistically significant. [Projekat Ministarstva nauke Republike Srbije, br. 031014]

A laboratory ball mill consisting of vertical cylinder, equipped with a rotating shaft with arms, and filled with steel balls as a grinding medium has been used in the experiments. The aim of the study was to examine the effect of agitator shaft speed and amount of grinding media (steel balls) on power requirements and energy consumption of a ball mill. With constant mass of the steel balls (20 kg, 30 kg and 40 kg), the agitator shaft speed was increased from 10% to 100% of the maximum speed which corresponds to a speed of 50 rpm. The power consumption (W) was recorded upon which milling energy consumption (J/kg) has been calculated. The results were statistically analyzed using ANOVA. The increase of the agitator shaft speed, in steps of 10% to the maximum speed of 50 rpm, led to a statistically significant increase in milling energy consumption. At low agitator shaft speed (10%), increase in the mass of the steel balls had no influence on the power requirements. Power requirements for the grinding runs using 30 kg and 40 kg are similar and higher compared to power requirement in trial with 20 kg, as agitator shaft speed increases from 20% to 70%. At high agitator shaft speeds (≥80%), increase in steel balls mass led to the significant increase in power requirements of the ball mill.

The breakage matrix approach is a mathematical tool to relate input and output particle size distribution from a milling operation. Adjustment of the break release in the flour milling process is extremely important because it affects granulation and quality characteristics of the stock and hence the total results and balance of the mill. In this study the breakage matrix approach has been used for the purpose of controlling the release on the front passages of the break system in the flour milling process.It has been established that, for any particle size distribution of wheat, it is possible to predict break releases together with the distribution of the release size fractions by using the breakage matrices. Also, the reversibility of this approach is examined, that is the possibility to identify the wheat particle size distribution that would result in desired break releases and/or the desired yields of different sized intermediate stocks under the given set of milling conditions.It is confirmed that the breakage matrix approach can be successfully used to predict the break releases. The reverse breakage matrix concept allows the determination of the wheat particle size distribution which would result in a targeted break release. © 2016 Society of Chemical Industry.

One of the potential raw materials which could be used for production of food with added nutritional value is tomato pomace, a by-product from tomato processing. On the other hand, requirements of consumers for diverse food with potential for health benefits impose the need for creation of products made from different cereals. In this respect, the aim of this study was to evaluate the influence of addition of dried tomato pomace on the physical and sensory properties of whole grain rye flour cookies. The whole grain rye flour was substituted with tomato pomace powder in two levels (15% and 25%) in the standard formulation of short-dough cookie. The quality of final products was evaluated by instrumental and sensory methods. The results clearly demonstrated that redness (+a*) and yellowness (+b*) were highly influenced by level of tomato pomace in the cookie formulations due to its content of carotenoid pigments. The spread factor of the cookies made with addition of tomato pomace powder was higher than the control sample. Hardness of the cookie samples decreased for approximately 50% for the cookie sample with 25% tomato pomace level substitution when compared with control sample. According to the results of sensory analysis, substitution level of 15% caused decrease of surface roughness, fracturability, and granularity, as well as increase of caramel flavour intensity. Substitution level of 25% caused higher degree of cookie softening and more pronounced tomato flavour.

Cookies are a popular confectionery product with a unique texture and taste, long shelf life and a relatively cheap price; therefore, it is a widespread snack among people of all generations. Nevertheless, cookies are usually made of wheat flour and most formulations are highly caloric and have a low fiber content. Soy flour is an excellent source of proteins, fibers, vitamins and minerals and it is being considered as a great supplement to wheat flour because it increases nutritive characteristics of the final product. By their digestibility and amino acid content, soy proteins are very similar to proteins derived from animals. They also contain many essential amino acids, which are deficient in most of the cereals. The purpose of this work was to determine the effect of soy flour on quality of cookies. Wheat flour was supplemented with 35% of soy flour (full-fat toasted, low-fat toasted, defatted lightly toasted, toasted and soy protein concentrate). The supplementation of wheat flour with soy flour had affected nutritive value and sensory characteristics of cookies.

Considering the significant differencies between the chemical composition of the kernel layers, distribution of chemical compounds in intermediate, final and subproducts of the milling process come as a result of the level of dissociation achieved during the milling process. These differences serve as a basis for the mill process control. Ash determination is probably the most widely used tool while even greater differencies exist in cellulose and especialy starch content. In this work efficiency function has been defined and used to evaluate the relative efficiency of the separation of endosperm from the outer pericarp leyers of the kernel. It is based on quantity rates (flour extraction and subproducts yield) and qulitative analyses (starch and cellulose content in the wheat, flour and subproducts).

Rationalization of the wheat flour milling process using the eight-roller mill on the front passages of the reduction system has been investigated. At the same roll gaps and same sieving conditions, a lower flour yield and a higher energy requirements for grinding have been obtained using an eight-roller mill compared to a conventional one. With appropriate adjustment of the roll gap and sieving conditions in the process with the eight-roller mill, it is possible to achieve similar milling results to those obtained with a conventional mill, while the investment costs and overall energy requirements are significantly lower. This justifies the use of the eight-roller mill on the front passages of the reduction system.

Poultry diets are mainly used in pelleted form because pellets have many advantages compared to mash feed. On the other hand, pelleting causes reduction of feed particle size. The aim of this research was to investigate the possibility of increasing the content of coarse particles in pellets, and, at the same time, to produce pellets with satisfactory quality. In this research, the three grinding treatments of corn were applied using hammer mill with three sieve openings diameter: 3 mm (HM-3), 6 mm (HM-6) and 9 mm (HM-9). These grinding treatments were combined in pelleting process with three gaps between rollers and the die of pellet press (roller-die gap, RDG) (0.30, 1.15 and 2.00 mm) and three moisture contents of the pelleted material (14.5, 16.0 and 17.5%). The increased coarseness of grinding by the hammer mill resulted in the increased amount of coarse particles in pellets, especially when the smallest RDG was applied (0.30 mm), but pellet quality was greatly reduced. Increasing of RDG improved the quality of pellets produced from coarsely ground corn, but reduced the content of coarse particles in pellets and increased specific energy consumption of the pellet press. Increasing the moisture content of material to be pelleted (MC) significantly reduced energy consumption of the pellet press, but there was no significant influence of MC on particle size after pelleting and on the pellet quality. The optimal values of the pelleting process parameters were determined using desirability function method. The results of optimization process showed that to achieve the highest possible quantity of coarse particles in the pellets, and to produce pellets of satisfactory quality, with the lowest possible energy consumption of the pellet press, the coarsest grinding on hammer mill (HM-9), the largest RDG (2 mm) and the highest MC (17.5%) should be applied.

6th International Dietary Fibre Conference, Paris, France 1-3 June 2015.

Introduction of the eight-roller mill into the wheat flour milling process significantly reduces the investment costs and overall energy requirements compared to the conventional milling system. However, the conditions for controlled milling are less favorable and could result in deterioration of flour yield and quality. Paper compares milling results obtained using a conventional process and process with an eight-roller mill employed on the tail-end passages of the reduction system. At the same roll gap and under the same sieving conditions, the flour release was lower in the process with the eight-roller mill compared to the conventional milling system. By decreasing the roll gap and increasing the upper size limit (granulation) of flour in the process with the eight-roller mill it is possible to increase flour yield and decrease milling energy consumption per unit mass of flour produced. This can be achieved without deterioration of flour quality as determined by ash content. [Projekat Ministarstva nauke Republike Srbije, br. 031014]

Mathematical relationship, in the form of matrix equation, for predicting the compositional distribution along with particle size distribution of the wheat flour stocks following first break milling of wheat, has been defined. Predictions were compared with the actual particle size and compositional distributions obtained by experimental milling. High average accuracy of predicting particle size distribution (97.42%), ash content in the size fractions of the milling output (94.66%) and protein content in the size fractions of the milling output (97.43%) confirms that breakage matrix approach can be successfully used for predicting compositional properties of flour stocks as well as their size distribution.