Goat's milk is positioned as biologically complete, suitable for the creation of functional products and baby food products. This is explained by the qualitative and quantitative composition of its main nutrients: proteins, lipids, carbohydrates, biologically active substances, micro- and macro-elements. The biological value of food raw materials is assessed by its ability to satisfy protein needs. Strict thermal treatment regimens are used for goat milk. This is caused by the quantitative ratio of casein and albumin fractions in goat milk and its specific organoleptic properties. Pasteurization of milk causes partial destruction of proteins, enzymes, hormones and evaporation of gaseous. This contributes to the improvement of sensory properties of dairy goat raw materials. The effect of high temperatures on goat milk proteins and its biological value has been little studied. The effect of pasteurization regimes on proteins was studied and indicators of the biological value of the samples were determined: without heat treatment; heat treatment 63 ± 2 °С, duration 30 minutes; heat treatment 87 ± 2 °С duration 5-6 minutes. The amino acid composition of the test samples was determined by acid hydrolysis on an LC2000 amino acid analyzer (Biotronik, Germany). Indicators of the biological value of proteins of pasteurized goat milk were calculated – coefficient of difference of amino acid composition, biological value, coefficient of utilitarian amino acid composition, coefficient of rationality of amino acid composition, coefficient of comparative redundancy. The general analysis of the obtained data revealed a positive effect of heat treatment on the indicators of the biological value of goat milk. The amino acid score of the limiting amino acid increased by 14.82–14.92 %; biological value – 11.4–13.02 %; the PDCAAS indicator – by 14.18–14.29 %; changes in the values of formalized indicators had the same tendency. The biological value of proteins for the application of thermal regimes is at the same level. It has been proven that pasteurization has a positive effect on the biological value of goat milk proteins. This makes the product safe and useful for all segments of the population and can be recommended for feeding children from 0 to 6 months. Prospects for further research are the development of milk drinks of a combined composition of raw materials with an improved recipe in order to enrich the product with limiting amino acids.

This article investigates processed cheese's nutritional value and safety by adding vegetable additives (dry Spirulina powder). Processed cheese for lunch is taken as a basis for the formulation. As a control, we took cheese made according to classical technology. We used cheeses from cow's milk. We used combined raw materials in the developed technology: cow's and goat's milk cheeses. Spirulina was added to the formulation as an enrichment agent in the 1%, 2%, and 3% ratio, respectively. The sample with a 1% addition was found to be rational according to the results of the organoleptic evaluation. The formulation was optimised in further study by selecting 0.5%, 1.5% and 2%. A centre composite plot was used to add points around the pre-lagged optimum. A regression formula was obtained, and the melting salts and the dosage of the added enrichment agent were determined. Also, the share of cheese from goat's milk in the recipe of processed cheese was determined. The recipe was calculated on the principle of material balance. Experimental samples were examined for fatty acid and amino acid composition. The tables compare the best sample on organoleptic evaluation with the control.  It was found that when 3% is added, the cheese acquires a dark green tinge. The colour is deep green when 2% is added; when 1% or less is added, the colour is salad. The dose of melting salts in the recipe was reduced to 2%; in the classic recipe, it was 3.9%.   The protein of the experimental sample turned out to be closer to the ideal protein. PDCAAS is equal to 96.9, while in the control sample, PDCAAS is equal to 39.9. Also, when comparing the fatty acid composition, the thrombogenicity coefficient was lower in the experimental sample than in the control.

Las necesidades nutricionales son una opción para diversos tipos de alimentos funcionales, como la granola a base de cereales andinos, siendo así una alternativa de snack saludable. El presente artículo tiene como objetivo en calcular, elaborar y analizar mezclas de granos andinos (quinua, cañihua, kiwicha y avena) cumpliendo con el requerimiento proteico para un adulto. El método que se utilizó en esta investigación fue el PDCAAS, que depende de la composición proteica de las hojuelas. Los resultados obtenidos en la evaluación sensorial de acuerdo a la aceptabilidad de los consumidores fue la muestra 4 que contiene H. quinua 314 g., H. cañihua 154 g., H. kiwicha 338 g, y H. avena 193 g, las mezclas contienen la cantidad necesaria de aminoácidos esenciales según el patrón de referencia donde el límite mínimo y máximo de la lisina es 45-52 mg/g proteína, aminoácidos azufrados 22-39.36 mg/g proteína; treonina 23-30.4 mg/g proteína, triptófano 6-9.84 mg/g proteína. Los análisis proximales que se realizaron en las diferentes muestras dieron como resultado: Ceniza (1.7 a 2.1 %), Humedad (5-10 %), Aw (0.25 – 0.30 aw), Proteína (15.4 %), Grasa (32.2 %), fibra (5.2%) y el color influye en las distintas muestras. En conclusión, la granola elaborada cumple con los requerimientos de la FAO, que se realizó mediante cálculos del PDCAAS obteniendo 30 formulaciones, en la cual se optimizo, quedando así 6 formulaciones para los análisis sensorial y fisicoquímicos. | JULIACA | Escuela Profesional de Ingeniería de Industrias Alimentarias | Tecnología de Cereales, Leguminosas, Raíces y Tubérculos

As part of a research grant aimed at producing chicken feed from the novel microalgae Scenedesmus sp., called the ReMAPP project, this thesis investigates opportunities to increase the conservation potential and protein digestibility utilizing solid-state lactic acid fermentation and commercial enzyme additives. The lactic acid fermentation mimics the traditional agricultural ensiling process, where crops are anaerobically fermented at room temperature for upwards of a year. The ensiling process conserves the material by using lactic acid bacteria to convert water soluble carbohydrates in the biomass to mainly lactic acid, lowering the pH and preventing growth of pathogens. This approach to microalgae conservation has not been attempted previously. Enzyme additives are hypothesized to degrade cell wall polymers to monosaccharides and are used to increase the substrate for lactic acid production, further decreasing the pH and thus improving the silage quality of the microalgae. At the same time, the protein digestibility of the specific microalgae species is hypothesized to be limited by bioavailability as the incalcitrant cell wall of Scenedesmus could prevent access to intracellular proteins, rendering them indigestible. The same enzyme additives used to improve fermentation could also affect the protein digestibility, since degradation of cell wall polymers could release intracellular proteins. To investigate the fermentation properties and protein digestibility, lab scale fermentations are carried out where Lactoplantibacillus plantarum and a variety of enzyme additives are mixed with Scenedesmus sp. biomass and left in vacuum-packed bags to ferment for 21 days. The results show bacterial inoculation by itself to be effective in decreasing pH to desirable levels but fermentation with β-glucanases, which seem to degrade polyglucans to glucose which are consumed by the lactic acid bacteria, proved the most effective. Only fermentations with β-glucanases achieved pH < 4.0, a benchmark for product safety. The effect on protein digestibility did however seem to be largely negligible. Lactic acid fermentation by itself did increase the protein digestibility, measured in PDCAAS, from 0.79 to 0.83 which is a relevant increase but still below the gold standard set by soybean. Using additional enzymes had only a marginal effect on increasing protein digestibility, and as such the hypothesis of degrading the cell wall to increase protein digestibility cannot be confirmed by this study. Endoproteases increased protein digestibility the most, the do likely not increase protein digestibility by degrading the cell wall but rather by hydrolyzing peptides. The most successful non-protease in terms of protein digestibility was a pectinase which was unexpected since no galacturonic acid, the main monomer of pectin, could be detected in the sample. To determine the cause of increase in protein digestibility and the effect pectinases have on the biomass, in-depth characterization on the biochemical composition of Scenedesmus sp. would be required. In conclusion, solid-state fermentation of Scenedesmus sp. biomass using lactic acid bacteria and enzyme additive was successful and could potentially be a useful conversation method for green microalgae in general. While some enzymes tested did yield an increase in protein digestibility where a pectinase and an endoprotease proved most effective, the hypothesis of releasing intracellular proteins to increase digestibility in combination with fermentation could not be confirmed. | Microalgae are, as the name implies, microscopic individual algae cells which are present in almost every natural water source in the world. Thousands of different types of microalgae exist, where a few have been found to both be easy to grow in reactors and contain a lot of protein. One recently discovered kind, called Scenedesmus sp., is up to 55% protein and grows quickly which makes it an interesting candidate for creating cheap and sustainable chicken feed. The science of using microalgae in food and feed is very new, and a lot of research is required to make production cheaper and competitive with already existing feed alternatives like soybeans. Two of many important questions to answer to create a successful product is how to store the algae without it rotting and how to draw out protein out of the algae cells. The first question is applicable to many foods. If the algae are left for too long dangerous bacteria will grow on it, making in unsuitable to eat. How can we prevent this? The second question is more specific to microalgae. The small cells have thick cell walls, which can be thought of as a shell and prevents the animals eating the algae from absorbing the protein since the protein is inside the shell. Can breaking the cell wall increase the amount of protein which the animals can absorb? This project attempts to answer both questions using the same method: fermentation with both lactic acid bacteria and enzyme mixtures. Lactic acid fermentation is a very popular method in many foods, like when creating sauerkraut and kimchi. Essentially, safe bacteria (in this case one called Lactoplantibacillus plantarum) consume the sugars in the algae and create lactic acid, which makes the whole material very acidic. Other dangerous bacteria which cause rotting cannot grow in high acidity, and as a result the algae are preserved. To improve the fermentation, enzymes which break down the cell wall into smaller parts can be used. The cell wall is in large part composed of cellulose, which is a long molecule composed of many individual sugar molecules. The enzymes release the individual sugars from the cellulose, which the lactic acid bacteria can eat and create more acid to make the material even more inhospitable to dangerous bacteria. At the same time, it is hypothesized that the cell wall being broken down by the enzymes could also release proteins from the inside of the cell. The same enzymes which improve the fermentation quality could as a result also be found to increase the protein digestibility of the microalgae. The study did find the fermentation part of the project to be successful. The acidity of the algae did increase significantly when only fermenting with the added safe bacteria. When also adding the cell wall degrading enzymes called β-glucanases, the algae became even more acidic, to the point where it is acidic enough deny any growth of dangerous bacteria. It was also found that a lot more of the sugar in the algae had been eaten when the enzymes were added, which indicates that the hypothesis was correct. However, no such clear confirmation could be found in increasing the protein digestibility. Even though the cell wall seemed to be damaged, almost no difference in protein digestibility was detected. Some enzymes did have an effect. Endoproteases increased protein digestibility, although they break down proteins into smaller parts which are more easily digested which means they work in a different way than what was hypothesized to increase the protein digestibility. Another enzyme, pectinase, was found to be somewhat successful in increasing the digestibility. However, pectinases only break down a substance called pectin, which could not be found in the algae. It is therefore unknown why it worked at all. To conclude, while fermentation seems to be a good way to conserve algae, it could not be said to have a meaningful effect on increasing the protein digestibility.

To meet global protein demand sustainably in the future, we have to move to alternative, non-animal sources. A problem of many plant-derived foods is their low protein quality compared to animal-based proteins, in particular their deficiency in lysine. To improve the protein quality, plant proteins could be converted to fungal proteins using solid-state fungal fermentation (SSFF). In this project Rhizopus microsporus var. oligosporus and Aspergillus oryzae were used to ferment barley and rice, producing tempeh and koji, respectively. SSFF yielded products with 6–13% (dry weight basis) fungal biomass. Protein quality was defined by the parameters indispensable amino acid index (IAAI) and protein digestibility corrected amino acid score (PDCAAS). SSFF improved both parameters in all samples. Lysine was the limiting amino acid in unfermented barley and rice, with PDCAAS of 0.54 and 0.57, respectively. SSFF increased the PDCAAS of lysine by approximately 30% in barley koji, barley tempeh and rice koji and 10% in rice tempeh. These results demonstrate the use of SSFF to improve the protein quality of staple foods. Thereby, this fermentation method can aid in meeting protein demands sustainably in the future through plant-based diets.

Soy protein isolate and egg white protein were added to cassava-banana gluten-free pasta and the effects on the nutritional quality, digestibility properties, protein digestibility corrected amino acid (PDCAA), and sensory acceptance of the pasta was observed. Banana-cassava composite flour (75:25) was blended with soy protein isolate or egg white protein at the following rates: 0, 5, 10, and 15 g/100 g flour. Cooked pasta samples were analysed for total phenolic content (TPC), antioxidant activity, amino acid profiles, protein content, starch digestibility, protein digestibility and protein digestibility corrected amino acid score (PDCAAS). Addition of both proteins decreased starch digestibility, increased protein digestibility, improved the balance of the amino acid profile, and PDCAAS whereas only soy protein isolate enhanced the TPC and antioxidant capacity of the banana-cassava pasta. An egg white protein-fortified banana-cassava pasta had better customer acceptance and purchase intent than soy protein isolate inclusion.

International audience | In the context of the search for new sources of protein to meet the growing demand for alternatives to animal sources, single cell proteins (SCP) represent a fast-growing sector. However, due to their high content in nucleic acids, their uses in human food are limited. SCP from yeast (Y1) and bacteria (B1) with decreased nucleic acid content have been produced and our objectives were: 1) to evaluate their protein quality and 2) to determine the effect of 50 days of SCP intake on health-related parameters in rats. In a first study, protein efficiency ratio (PER) was determined in young Wistar rats fed a diet containing either casein (control), Y1 or B1. Faecal digestibility was evaluated thanks to 15N-labelled proteins and PDCAAS of Y1 and B1 were calculated. In a second study, Wistar rats were fed a casein, Y1 or B1 diet during 50 days. Food intake and body weight were daily measured and urine and plasma were collected at 0, 25 and 50 days. PER of B1 (2.2±0.1) and Y1 (1.9±0.1) were lower than casein (2.5±0.1, P<0.001). Faecal digestibility of Y1 (76.6±5.1%) and B1 (79.7±4.8%) were similar but low compared to casein (93.7±1.1%, P<0.001). However, thanks to a balanced indispensable amino acids profile, PDCAAS was good (0.9, leu) for Y1 and excellent (1.1) for B1. In addition, 50 days of Y1 or B1 diet did not alter food intake, body weight or body composition, and plasma metabolic parameters and inflammatory markers were similar to those of casein-fed rats. Increased urinary uric acid was observed with Y1 diet but without hyperuricemia, suggesting an efficient excretion of uric acid. In conclusion, despite a moderate PER, protein quality of Y1 and B1 was very good and no deleterious effect has been observed after mid-term consumption of these SCP.

The types and contents of proteins are different in different foods, and the composition and proportion of amino acids are different, as a result, their contribution to meeting the nutritional needs of the human body is different. As the most basic nutrient component of food, protein has a direct impact on human health. With the rapid increase of global population and limited resources, a scientific and reasonable protein quality evaluation method is very important for investigating reasonable diet, obtaining adequate nutrition, and effectively developing new protein resources and so on. Therefore, this paper reviews the research process of protein quality evaluation methods in food, and elaborates the protein digestibility corrected amino acid score (PDCAAS) and digestibility indispensable amino acid score (DIAAS), including the applications, advantages and limitations of these two evaluation methods. It is hoped to provide some theoretical basis for exploring high-quality protein sources and protein complementarity, and developing high-quality protein foods.