Zbigniew Kobus

Application of Freezing and Thawing to Carrot (Daucus carota L.) Juice Extraction

This paper presents a study of the effects of freezing and thawing carrot pulp and pomace on the efficiency of the pressing process and the quality of juice. In this study, various combinations of pretreatment strategies were used based on freezing and thawing the carrot pulp and pomace before pressing. The pressing process for pulp and pomace was carried out using a laboratory press with a perforated base. The juice obtained as a result of freezing and thawing the carrot pulp and pomace was characterized by a higher sugar content (°Brix) and a slightly lower dynamic viscosity. Furthermore, the study showed the impact of pretreatment on the chemical composition of the juice produced. On the basis of energy use and quality indicators of the resultant carrot juice (viscosity, pH, selected minerals, sugars, total carotenoid content, and vitamin C), a recommended solution is to press the pulp directly after grinding the carrots and then to press the pomace again after freezing and thawing. The proposed method for juice production using freezing and thawing allows a reduction in pomace quantity and the use of its valuable nutrients.

Changes in Particle Size Distribution of Bran and Flour Obtained from Vacuum Impregnated and Infra-red Heated Wheat Grain

This study aims to provide comprehensive information on the process of vacuum impregnation of wheat grains. Vacuum impregnation, saturating materials with additional liquid components, is a well-known process originally developed to ensure leak tightness or reduce the porosity of various materials. We describe its potential uses in the food processing industry relating to the impregnation of grains and leguminous plant seeds. The objective of the study was to determine the influence of impregnation and infrared heating of wheat grains on flour efficiency, moisture content and particle size distribution in the resulting flour and bran. The experimental material comprised three varieties of wheat. The results showed that the method of preparing the wheat grains for milling combined with impregnation had a significant impact on the particle size distribution of bran but not on the particle size distribution of flour. A more complete view of the process characteristics requires further investigation of factors related to the structural and textural properties of the impregnated material, factors which are highly varied in the case of food materials and food products.

Concept of Using Fruit Pomace on Sustainable Farms

The paper presents the possibility of using fruit pomace as the management of poor products on sustainable farms. Processing of raw materials in the fruit and vegetable industry involves generation of manufacturing waste, of which pomace that may be processed in different ways, constitutes the highest share. Pomace is most commonly used as fuel in biogas plants, or as feed additives. Despite its high microbial instability, pomace is a great source of numerous bioactive substances.Therefore, it may be used alternatively in the production of granulated fruit and herbal teas.The aim of this paper was to assess the possibility of using fruit pomace in the production of granulated teas with addition of Melissa officinalis. Material used in the study was the agglomeration of dried and fragmented black chokeberry and apple pomace blended with Melissa officinalis. Prepared granules were used to make infusions for which the total polyphenol content, antioxidant activity and sediment amount were determined.

Characterisation of Selected Apple Cultivars in the Aspect of Juice Production in the Condition of a Farm

Pressing is the most common method of fruit juice acquisition. Not all apple cultivars are suitable for juice pressing. The use of suitable fruit cultivars for juice pressing may reduce the cost of pressing and at the same time guarantee high quality of the juice produced. The scope of the study comprised the determination of pressing efficiency and of the quality parameters of apple juice obtained, such as acidity and the content of extract. The results of the study indicate that the efficiency of pressing and the quality of the juice obtained are significantly affected by the varietal traits of the apples. The choice of suitable cultivars allows to achieve a high pressing efficiency and to obtain juice characterised by a high content of extract and high acidity. INTRODUCTION Pressing is the most common method of apple juice acquisition (Markowski, Baron, Le Quéré, Płocharski, 2015). At present, juice pressing under industrial conditions is performed most frequently with the use of presses for periodic operation (mainly baskettype) and for continuous operation (screw-type presses, roller presses or belt presses) (Bump, 1989). Fruit processing methods employed on the industrial scale may significantly alter the nutritional properties of the fruits (De Paepe, Valkenborg, Coudijzer, Noten, Servaes, De Loose, Voorspoels, Diels, Van Droogenbroeck, 2014). Therefore, it is necessary to develop such methods of fruit processing that will minimise the negative effects of the processing on the health-promoting properties of the fruits (Rothwell, Medina-Remón, Pérez-Jiménez, Neveu, Knaze, Slimani, Scalbert, 2015). In certain countries orchard farms are equipped with complete lines for the pressing and delicate preservation of fruit juices. Recently one can observe a development of juice pressing services with the use of mobile presses, which means that juices are produced on site at the fruit producer’s farm (http://mobilejuicefactory.com/mobile-juicing/). As can be seen from the literature data, not all apple cultivars are suitable for juice pressing. The efficiency of the pressing process and the quality of the juice obtained depend on numerous factors, among which the technological properties of raw material play an important role (Renard, Le-Quéré, Baudin, Symoneaux, Le Bourvellec, Baron 2011). In Poland, more than 60 apple cultivars are entered in the National List of Varieties. However, there is a lack of complete knowledge on their applicability for juice pressing. The use of suitable fruit cultivars for juice pressing may reduce the cost of pressing and at the same time guarantee high quality of the juice produced (Eiselea, Drakeb, 2005; Sedov, Levgerova, Salina, Serova, 2010). This justifies research on various apple cultivars in the aspect of estimation of their applicability for juice pressing, especially in farm conditions (orchards), i.e. without the use of specialised preliminary processing of the fruits prior to pressing.

Assessment of Selected Technical Parameters of Soya Seeds Oil Pressing Process

Abstract The objective of the paper was to determine the impact of the value of the oil pressing pressure with the cold pressing method in a screw press on the pressing course and performance. Varied values of pressure were obtained through the use of three replaceable attachments of the pressing unit with a varied diameter of the outlet conduit (ф1=2 mm, ф2=4 mm and ф3=6 mm). The soya oil pressing process performance was determined in relation to the applied attachment and the soya cultivar. Seeds of 7 Polish non-genetically modified soya cultivars constituted research material. It was proved that both variable pressure values and the used soya cultivars have impact on the pressing performance. Based on the analysis of the obtained research results it was proved that varied technical parameters and soya cultivars influence both the process performance and the remaining parameters and pressing conditions.