Ivi Jõudu

This study aimed to maximise the content of water-soluble protein (WSP) and β-glucan (BG) in oat drink (OD) products by optimising the duration of treatment with neutral (NP) and acidic (AP) proteases. Additionally, it investigated the correlation between changes in the OD’s nutritional profile and its rheological and sensory properties. After initial treatment with α-amylase, the OD samples were divided into two groups, i.e., one treated with NP and the other with AP for 30, 60, 120, and 180 min. The samples were then analysed for their WSP and BG contents. Samples with an optimised treatment duration were evaluated for their rheological and sensory properties. The OD sample treated with AP for 60 min exhibited the highest β-glucan (0.52 g/100 mL) and WSP (1.56 g/100 mL) contents, improved storage stability, and the lowest sedimentation rate (2.13%/h), compared to the control OD sample. However, sensorially, this sample was characterised by a sticky, gluey mouthfeel and was less acceptable as a drinkable product. This study demonstrated the potential effect of protease treatment on enhancing the nutritional value and stability of OD products, although further studies are necessary to improve the sensory properties of these drinks.

Although "zero waste" valorization concepts are gaining increasing attention, colostrum, a byproduct of milk production, remains underused due to technological challenges. Information about the fat fraction and the size of fat globules is needed to address these challenges, but such information is currently lacking. This study aimed to fill this gap in the knowledge by measuring the size distribution of bovine colostrum fat globules (CFG) and analyzing its relationships with postpartum milkings, parity, and fatty acids (FA) profile. Four sequential postpartum colostrum samples were collected from 44 cows and analyzed for the abovementioned parameters. The results indicated that CFG size increases almost twice during postpartum milkings (from ∼5 to ∼10 µm), whereas lactation has little, if any, effect on CFG size. The FA profile analyses showed that the content of most FA in the fourth postpartum milking was different from the previous milkings. The correlation analyses between CFG size and FA profile also demonstrated that the fourth milking was clearly distinguishable from the first 3 postpartum milkings. For example, the saturated FA content from the first 3 milkings had a positive correlation with smaller CFG (and a negative correlation with larger CFG), whereas the fourth milking demonstrated no correlations. Based on these CFG size and FA profile analyses, the results of this study suggest that the first 3 postpartum milkings can be considered as colostrum, whereas the fourth milking represents transition milk. Information about CFG size distribution enables modification of the FA profile of colostrum products and the ability to create better valorization technologies for colostrum-based food and feed supplements.

There is an increasing tendency toward the application of plant origin ingredients in meat products. This study evaluates the physicochemical properties and oxidative stability of pork burger patties produced with the addition of dried raw and defatted by supercritical CO₂ extraction hemp seed press-cake as protein-rich ingredients (1.5–2.0%) and sweet grass ethanolic extract (0.5%) as a strong natural antioxidant. The main aim of using such a combination was to assess the possibility of mitigating the negative effects of hemp seed press-cake, containing approx. 10% of highly unsaturated oil, on the oxidation of meat products. The patties were compared with the control sample (without additives) during storage on days 0, 4, 8, 15, and 21 at 4 °C in modified atmosphere conditions. Plant ingredients reduced the lightness of pork patties, while their effects on other physicochemical characteristics were insignificant. The patties with fully defatted hemp seed flour showed the lowest grilling losses. Based on the measurement of thiobarbituric acid reactive substances, raw hemp seed press-cake increased the oxidative rate of pork patties; however, remarkably, the addition of sweet grass extract completely inhibited oxidation during the whole period of storage. The sensory characteristics of the products were acceptable; however, the patties with sweet grass extract received lower evaluation scores.

Bovine colostrum, as vital as it is for calves, is also a valuable source of functional components with rich health benefits for humans. Bovine colostrum whey consists of a large number of bioactive proteins and peptides. The most abundant of these is IgG. Particle size distribution (PSD) is an important feature of many of the processes in the dairy food industries. Despite this, scientific literature on PSD of colostrum whey is scarce. The goal of this research was to describe bovine colostrum whey PSD with an emphasis on postpartum milking time, filtration (pore size 450, 100, and 20 nm), IgG concentration, and lactation number. For this purpose, 4 postpartum milking colostrum samples were sequentially milked from 46 Holstein cows at 12 +/- 1 h intervals. Colostrum whey was prepared by renneting and diluted (1:200) for PSD analyses by a Malvern Zetasizer Nano ZS (Malvern Instruments Ltd., Malvern, UK). Immunoglobulin G concentration of these diluted colostrum whey samples were analyzed by an Octet K2 (Molecular Devices LLC, San Jose, CA) system. Linear mixed model analysis revealed significant effects of filter pore size, postpartum milking, and lactation on colostrum whey IgG concentrations. The percentage of particles in the size interval 5 to 15 nm (the hydrodynamic diameter of IgG is around 10 nm) had an intermediate positive correlation (r = 0.50) with IgG concentration. Furthermore, we showed that PSD was associated with IgG concentration, postpartum milking time, and lactation number. The PSD measurement results showed the mean hydrodynamic diameter of 100 nm pore size filtered colostrum whey to be around 10 nm. This, with the IgG concentration results, suggests that even though the size of IgG is around 10 nm, a 100 nm pore size is adequate for membrane-IgG separations. In terms of energy efficiency of the filtration process, the use of a larger filter pore size can make a remarkable difference, for example, in pressurizing and cooling costs. Our work contributes to the development of sustainable and widely available colostrum-derived food and feed supplements.

Sustainable utilization of agri-food wastes and by-products for producing value-added products (for cosmetic, pharmaceutical or food industrial applications) provides an opportunity for earning additional income for the dependent industrial sector. Besides, effective valorisation of wastes/by-products can efficiently help in reducing environmental stress by decreasing unwarranted pollution. The major focus of this review is to provide comprehensive information on valorisation of agri-food wastes and by-products with focus laid on bioactive compounds and bioactivity. The review covers the bioactives identified from wastes and by-products of plants (fruits, exotic fruits, vegetables and seeds), animals (dairy and meat) and marine (fish, shellfish seaweeds) resources. Further, insights on the present status and future challenges of sustainably utilizing agri-food wastes/by-products for value addition will be highlighted.

The size distribution of wheat-grain starch granules has an impact on the yield of fine flour. The aim of the study was to compare the impact of conventional (mineral fertilizers, pesticides) and organic farming treatments (cover crops, composted cattle manure) on (i) the size distribution of starch granules, (ii) the level of the first break whole and fine flour yield. The grain samples of winter wheat cv Fredis were taken from a long-term field crop rotation experiment established in 2008 at the Estonian University of Life Sciences in Tartu County (58°22′ N, 26°40′ E) on Stagnic Luvisol soil. The weather conditions during the grain filling period of winter wheat had a strong impact (p < 0.001) on the grain starch granule size distribution. The proportion of starch granules with a smaller diameter (C-type granules) was higher in years with a longer grain filling period. The size distribution of starch granules was not influenced by farming system. The increased proportion of C-type granules increased the fine flour yield significantly. Fertilisation with organic manure and twice with mineral nitrogen increased significantly the mean diameter value of different starch granules.