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Evaluation of hemp protein flours stability
NĚMCOVÁ, Hana
The aim of this diploma thesis is to explore the possibility of storage of hemp protein concentrates extracted by mechanical sifting of milled hemp (Cannabis sativa) seed cake. On the ground of previously acquired scientific knowledge two size fractions of hemp flour were prepared - protein flour containing particles lower than 180 m and fibre flour containing particles larger than 180 m. The two types of flours were subsequently stored for the period of eight months in different conditions. On the stored samples and on the samples before the attempted experience were evaluated following parameters: dry matter, fat content, titratable acidity, antioxidant activity and polyphenol content. The diploma thesis found out the evaluated parameters are statistically significantly affected by the flour's fraction. The type of storage has statistically significant effect on all the parameters, except of the antioxidant activity. The analysis showed that the storage is less suitable for fraction containing less than 180 m because the fraction containing particles less than 180 m is more likely to go rancid given to the larger fat content, shows lower antioxidant activity, contains less polyphenols and tends to become moister. Better outcomes were showed by samples stored in vacuum, of which samples stored at a temperature of 5 °C showed even better results. These samples revealed lower fat dissociation, lower acidity and higher antioxidant activity. However, 9 % moisture that could lead to higher microbial strain was observed.
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Preparation of hemp protein concentrates by mechanical method
NĚMCOVÁ, Hana
A large amount of residual material, which is rich in high-quality protein containing all essential amino acids, remains after pressing hemp seed oil (Cannabis sativa L.). This "waste" can be ground into flour. This thesis examines whether dry sieving of hemp flour could increase the protein concentration in some size fraction to such an extent that it could be used as a protein concentrate. The experiment was carried out on five varieties of hemp from which was the cold-pressed oil acquired. The ground flour was subsequently divided into three size fractions. The coarsest fraction contained particles larger than 250 m, the middle fraction consisted of particles smaller than 250 m but larger than 180 m and the finest fraction composed of particles smaller than 180 m. Proteins were analyzed by various laboratory techniques. Most proteins were found to be in the finest fraction. Their concentration increased here from about 24-27 % to 35-40 %.
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Enzyme hydrolysis of potato proteins and possibilities of fractionation of obtained peptide fragments
MIKOVÁ, Klára
The diploma thesis is focused on enzyme hydrolysis of potato protein concentrates and fractionation of obtained peptide fragments. Were used protein concentrate from tubers variety Ornella and protein concentrate obtained by swedish company Lyckeby Starch AB. The enzyme hydrolysis lasted 24 hours and were used the proteolytic enzyme alkalasa and trypsin. In this work were prove possitive effect of enzyme hydrolysis on solubility and antioxidative properties of potato protein isolates. The fractionation of obtained peptide hydrolysated was based on systém FPLC (Fast protein liquid chromatography). The fractions contained of peptide fragments about 1, 350 kDa or fragments of smaller moleculary weight. The antixodative activity of subfractions were determIne by method called DPPH. The highest values (2,2 and 2,6 TEAC g/kg) were accured at the subfractions which were separations from Ornella hydrolyzates digeste by enzyme alkalasa.
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