Beijing Institute of Nutritional Sources

Milk protein is an important component in milk and dairy products, and its content and composition are important factors influencing the functionality of milk such as nutrition and immunity. Protein components in milk are complex, and the content of different components varies greatly. With the development of functional properties of milk protein, it is of great significance and value to determine the content of milk protein components in a faster and more accurate way. Currently, enzyme-linked immunosorbent assay (ELISA), capillary electrophoresis (CE), high performance liquid chromatography (HPLC) and high performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) are the main methods used to determine protein components in milk. In this article, the measurement principle, applicability, and the characteristics of these methods are reviewed, which could provide reliable technical reference for accurate measurement and establishment of a novel method in milk protein evaluation, while this could also be a theoretical support for dairy nutrition research, development of dairy products and infant formula optimization.

To research the effect of sodium alginate intervention on the nutritional intake of healthy young men. Recruited 20 healthy university students as research subjects. The experiment was divided into two periods: the dietary balance period and the sodium alginate intervening period, and each period was expected to be 28 days. During the dietary balance period, all meals in every day of experiment are provided by the research team; during the sodium alginate intervening period, based on the diet during the balanced diet period, sodium alginate was added to the staple food steamed buns(10 g sodium alginate per person per day). The experiment compares the food intake types, main nutrient intake levels and serum amino acid changes of subjects before and after intervention. Adding sodium alginate can significantly reduce the intake of energy(-242.4 kcal), protein(-11 g)and carbohydrates(-47.3 g, P<0.05)in healthy subjects, but there was no significant effect on the intake of fat(-2.9 g, P=0.496)and cholesterol(-14.9 mg, P=0.070), and because of the addition of alginate, the whole dietary fibers obtained a significant increase(+7.8 g, P<0.05). After the intervention of sodium alginate, there was no significant change in the intake of rice, soy products, poultry products and vegetable oil, while the intake of wheat products(-49.6 g), egg foods(-2.6 g), dark-colored vegetables(-29.1 g), light-colored vegetables(-63.8 g)and fruits(-37 g)decreased significantly(P<0.05). Most of the essential amino acids in the subjects' serum increased significantly after the intervention, especially the valine in serum rise from 226.9 μmol/L to 466.4 μmol/L(P<0.05). Sodium alginate can play a dietary fiber-like effect, produce satiety, reduce nutrient intake of subjects, especially carbohydrates, so sodium alginate has the potential to limit energy intake and control postprandial blood sugar. And sodium alginate also has a potential positive effect on the metabolism of amino acids in healthy people, especially the metabolism of essential amino acids.

Casein-derived antioxidant peptides by using microbial proteases have gained increasing attention. Combination of two microbial proteases, Protin SD-NY10 and Protease A "Amano" 2SD, was employed to hydrolyze casein to obtain potential antioxidant peptides that were identified by LCMS/ MS, chemically synthesized and characterized in a oxidatively damaged HepG2 cell model. Four peptides, YQLD, FSDIPNPIGSEN, FSDIPNPIGSE, YFYP were found to possess high 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging ability. Evaluation with HepG2 cells showed that the 4 peptides at low concentrations (< 1.0 mg/ml) protected the cells against oxidative damage. The 4 peptides exhibited different levels of antioxidant activity by stimulating mRNA and protein expression of the antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px), as well as nuclear factor erythroid-2-related factor 2 (Nrf2), but decreasing the mRNA expression of Kelch-like ECH-associated protein 1 (Keap1). Furthermore, these peptides decreased production of reactive oxygen species (ROS) and malondialdehyde (MDA), but increased glutathione (GSH) production in HepG2 cells. Therefore, the 4 casein-derived peptides obtained by using microbial proteases exhibited different antioxidant activity by activating the Keap1-Nrf2 signaling pathway, and they could serve as potential antioxidant agents in functional foods or pharmaceutic preparation.

Objectives: To provide scientific and practical criteria for Nutrient Profiles (NP) in China in order to evaluate the overall nutritional quality of solid pre-packaged food according to their nutrient composition.&#x0D; Methods: Based on data obtained from a survey of experts’ grading of foods available in China, a NP model was established, which covered scope of application, choice and balance of nutrients, choice of benchmarks and algorithm used. &#x0D; Results: A NP model for solid foods was established as a scoring model, the reference amount was 100 g. The recommended intake standards were Nutrient Reference Value (NRV) in labeling regulation. Nutrients taken into account included qualifying nutrients (dietary fiber, vitamin C) and disqualifying nutrients (total fat, saturated fatty acid (SFA), sodium). A total score was calculated as (score of dietary fiber + score of vitamin C) – (score of total fat + score of SFA + score of sodium). Foods with a total score ≤-5were qualified as "less healthy", a score of -4 ≤ total score ≤ 2 was "intermediate" and a total score ≥3 indicated "healthier".&#x0D; Conclusion: A NP model for pre-packaged foods in China was established that can be used to assess and compare the impact of different foods on diet, and help decide which pre-packaged foods are qualified to carry nutrition and health claims.

The in vitro inhibitory effect of sprouted quinoa yoghurt beverages (QYB) fermented with anti-diabetic lactic acid bacteria on α-amylase was investigated. In vitro studies using porcine pancreatic α-amylase showed that quinoa yoghurt beverages fermented with Lactobacillus casei Zhang and Lactobacillus casei SY13 dose-dependently inhibited the activities of α-amylase. The saponin content, reducing and total sugars were also quantified to determine their potency as anti-hyperglycemic agents against type 2 diabetes mellitus. The saponin contents of the yoghurt beverages were relatively low at a range of 0.19–0.41%, and significantly reduced as germination time increased. Germination significantly decreased the reducing sugars in all samples. A total of 4 sugars were identified using HPLC. Quinoa yoghurt beverages can be targeted as a potential dual-inhibitory strategy to attenuate type 2 diabetes mellitus by their ability to inhibit α-amylase activity as well as reduce or prevent hyperglycemic conditions associated with elevated levels of sugar glucose in the blood.

Taking Beijing city as an example, the relationship between aging of population, the consumption and the GDP in large city were studied based on the VAR model in the article. The results showed that there are closely relationship between the ratio of elderly dependency and consumption and economic growth. The population aging has a positive impact on household consumption increased with aging slightly, but there was a weak negative effect on economic growth. In view of the influence of population aging, the suggestions such as improving the social security system, developing new pension industry and promoting the optimization and upgrading of the dietary structure were put forward to realize the population, economic and social aspects developing synergistically.

Production of omega-3 polyunsaturated fatty acids concentrates from oil of Schizochytrium limacinum was optimized to obtain the highest omega-3 polyunsaturated fatty acid (ω-3PUFA) enrichment ratio. In this process, the content of docosapentenoic acid (DPA), the content of docosahexenoic acid (DHA) in the final product, the percentage recovery of the heavy phase, and the ω-3PUFA enrichment ratio were optimized. Single-factor experiments were carried out to study the effects of evaporator temperature, feeding rate, feeding temperature, and roller speed. A central composite design was used to optimize technological conditions. Under optimum conditions, the highest ω-3PUFA enrichment ratio (92.98%) was obtained at an evaporator temperature of 110.4 °C, a feeding rate of 78.7 mL/h, a roller speed of 350 rpm, a feeding temperature of 80 °C, and an operating pressure 10 Pa.