Table of Content

01 March 2025, Volume 48 Issue 2

Previous Issue   

Basic Research

Improvement Effects of Different Prebiotics on the Characteristics of Probiotic Fermented milk with Bifidobacterium animalis subsp. lactis PB200

GONG Han, GUO Yue, WANG Gan’en, ZOU Yang, ZHANG Haijiao, DAI Ruitong, MAO Xueying

2025, 48(2):  1-8.  DOI: 10.7506/rykxyjs1671-5187-20241228-116

Asbtract ( )   HTML ( )   PDF (3004KB) ( )  

Related Articles | Metrics

In this study, four prebiotics including inulin, fructo-oligosaccharides (FOS), galacto-oligosaccharides (GOS), and yeast β-glucan were added singly (inulin) or in different combinations (inulin + FOS + GOS and inulin + FOS + GOS + yeast β-glucan) to fermented milk containing Bifidobacterium animalis subsp. lactis PB200. The titratable acidity, pH, whey syneresis and total viable count of the fermented milk were measured during storage periods. Moreover, the rheological and textural properties were measured. The aim was to clarify the effect of different prebiotic combinations on the yogurt system in order to obtain the optimal probiotic combination. Compared with the control group with no prebiotic added, the addition of prebiotics significantly delayed the post-acidification, and promoted the growth of B. animalis subsp. lactis PB200. Besides, the titratable acidity of fermented milk added with inulin, FOS, GOS and β-glucan was the lowest , and the titratable acidity increased slowly and whey syneresis was less with the extension of storage time. The addition of all four prebiotics could maintain a higher viable count of B. animalis subsp. lactis PB200. The results of rheological and textural analysis showed that yogurt added with all four prebiotics had higher gel strength, hardness, cohesiveness, gumminess, adhesiveness and springiness, showing better texture. In summary, the addition of inulin, FOS, GOS and β-glucan resulted in better quality of probiotic fermented milk with B. animalis subsp. lactis PB200.

Comparative Quality Analysis between High-Fat and Regular Yogurts

LI Chundong, XU Tong, GAO Yuan, LIU Guoqiang, HU Ri, XU Weiliang, MA Xinya, GAO Zhihai, JIRI Galatu, GUO Liang

2025, 48(2):  9-14.  DOI: 10.7506/rykxyjs1671-5187-20240729-071

Asbtract ( )   HTML ( )   PDF (2393KB) ( )  

Related Articles | Metrics

In this study, to understand the differences in quality between high-fat and regular yogurts, we compared the changes in viable bacterial counts, acidity, and textural characteristics between homemade high-fat and regular yogurts as well as commercial yogurt (two samples for each type of yogurt) during the shelf life. The results showed that the fat content (16.7% and 17.0%) and energy (731 and 721 kJ/100 g) of high-fat yogurt were significantly higher than those of regular yogurt, and the carbohydrate content (3.6% and 2.3%) was significantly lower than that of regular yogurt. High-fat yogurt possessed a strong fatty flavor and a thick texture. The acidity (90.62 and 91.15 °T) and viable bacterial count (9.15 and 8.95 (lg (CFU/mL))) of high-fat yogurt were lower than those of regular yogurt, whereas the hardness (22.45 and 26.15 g), adhesiveness (0.59 and 0.72 mJ) and chewiness (0.86 and 1.03 mJ) were higher than those of regular yogurt. Compared to commercial yogurt, the acidity of homemade yogurts is more stable, but basically the same viable bacterial count and textural characteristics. In conclusion, high-fat yogurt has lower carbohydrate content, acidity and viable bacterial count, and the high fat content not only imparts a fatty flavor to this yogurt but also improves its textural properties and stability.

Analysis & Detection

Optimized Gas Chromatographic Method for the Determination of Iodine Content in Liquid Milk

LIANG Lin

2025, 48(2):  15-19.  DOI: 10.7506/rykxyjs1671-5187-20240930-090

Asbtract ( )   HTML ( )   PDF (2119KB) ( )  

Related Articles | Metrics

The iodine content in liquid milk was determined via gas chromatography (GC). Through systematic screening and optimization of derivatizing reagents and derivatization time, higher measured values of the iodine content in liquid milk were obtained while solving the problem of poor repeatability of the traditional method. The optimized method was more efficient than the national standard method National food safety standard-determination of iodine in food (GB 5009.267-2020). The optimal pretreatment conditions were determined to be 1.0 mL of sulfuric acid, 2.0 mL of butanone, 0.5 mL of 3.5% (V/V) hydrogen peroxide, and derivatization reaction for 30 min. This study provides a reliable basis for this optimized scheme to achieve efficient and accurate detection of iodine in liquid milk and holds significant application value in the control of the iodine content in liquid milk.

Correlation between Feed Types and the Beany Odor of Raw Milk

LIU Yuru, LI Xinyi, CHEN Xiaomin, ZHANG Shuli, ZHANG Dexi

2025, 48(2):  20-29.  DOI: 10.7506/rykxyjs1671-5187-20241122-100

Asbtract ( )   HTML ( )   PDF (2108KB) ( )  

Related Articles | Metrics

To investigate the correlation between the beany odor of raw cow’s milk and feed types, this study selected two samples of raw cow’s milk with beany odor and five common feeds: soybean meal, alfalfa, flaked corn, oat grass, and corn silage, and measured their volatile flavor compounds by headspace solid phase microextraction-gas chromatography-mass spectrometry (GC-MS). Key flavor compounds were identified using relative odor activity value (ROAV). The results indicated that acids and aldehydes contributed primarily to the beany odor of raw milk. A total of 49 volatile substances were identified in the two milk samples, among which hexanoic acid, octanoic acid, decanoic acid, decanal, nonanal, (E)-2-octenal, and (E)-2-decenal were the main beany odor substances. A total of 257 volatile substances were detected in all feed samples, including decanal, nonanal, and (E)-2-octenal. According to ROAV analysis, the beany odor compounds were more abundant in the feed samples than in the milk samples. The relative contents of beany odor compounds in the feed samples followed the following decreasing order of alfalfa > oat grass > soybean meal > flaked corn > corn silage, and flaked corn exclusively contained vanillin, with a strong milky aroma.

Evaluation of Measurement Uncertainty in Microbiological Determination of Vitamin B6 in Milk Powder

LIU Lu, GU Shenglin, XIA Yawen

2025, 48(2):  30-34.  DOI: 10.7506/rykxyjs1671-5187-20241018-096

Asbtract ( )   HTML ( )   PDF (3830KB) ( )  

Related Articles | Metrics

To evaluate the measurement uncertainty in the microbiological determination of the vitamin B6 content in milk powder, we estimated various uncertainty sources according to the National food safety standard for the determination of vitamin B6 in foods (GB 5009.154-2023) and the Evaluation and expression of uncertainty in measurement (JJF 1059.1-2012), and calculated combined standard and extended uncertainties. The results showed that the content of vitamin B6 in milk powder was (9.34 ± 1.23) mg/kg (k = 2, p = 95%). Through uncertainty component analysis, it was found that measurement repeatability and the preparation of standard solution had a significant impact on the determination of the vitamin B6 content in milk powder.

Reviews

Research Progress on Folic Acid Health Effects in Newborns and Folic Acid in Human Milk

JIA Hongxin, SU Miya, CHEN Wenliang

2025, 48(2):  35-39.  DOI: 10.7506/rykxyjs1671-5187-20240930-089

Asbtract ( )   HTML ( )   PDF (1782KB) ( )  

Related Articles | Metrics

Folic acid is a very important water-soluble vitamin in human milk, which is essential for embryonic development and growth. The folic acid in human milk often exists in the form of polyglutamic acid salts (≥ 4 glutamyl residues), such as 5-methyltetrahydrofolate. Folic acid deficiency may lead to birth defects such as neural tube defect and congenital heart disease. This article introduces the folic acid content in breast milk from different countries/regions, the factors influencing it and its health effects in order to provide a reference for the development of infant formula milk powder.

Application of Next Generation Sequencing Technology in the Quality and Safety of Dairy Products

CHEN Wanyi, ZHONG Fuxia, LIU Xiaoyan, YAO Lu, JU Wantao

2025, 48(2):  40-46.  DOI: 10.7506/rykxyjs1671-5187-20241008-092

Asbtract ( )   HTML ( )   PDF (1589KB) ( )  

Related Articles | Metrics

Next generation sequencing (NGS) is a new sequencing method invented at the beginning of the 21st century on the basis of first-generation sequencing technology. With its high throughput, high accuracy and abundant genetic data, NGS has been gradually applied to the dairy industry and has played an important role in ensuring the quality and safety of dairy products. On the one hand, this paper introduces the application of whole genome sequencing (WGS) technology to identify contaminated microorganisms, pathogen traceability, strain polymorphism, antibiotic resistance and virulence factor carrying status analysis. On the other hand, this paper focuses on the application of metagenomic sequencing technology in research on the application of microbial diversity, including microbial diversity investigation in the processing environment of dairy products, environmental microorganism monitoring of dairy factories, shelf-life assessment of dairy products, microbial risk monitoring of raw materials, and authenticity assessment of dairy products. Finally, this paper comprehensively analyzes and discusses the challenges and future prospects for the application of NGS technology in the field of dairy products.

Research Progress on the Formulation and Nutritional Components of Nutritionally Complete Foods for Special Medical Purposes for Children Aged 1-10 Years

LIU Yue, GENG Xue, LUO Xiaoju, WANG Xueyin, WANG Bin

2025, 48(2):  47-46.  DOI: 10.7506/rykxyjs1671-5187-20241122-099

Asbtract ( )   HTML ( )   PDF (2083KB) ( )  

Related Articles | Metrics

The formulation and nutritional characteristics of nutritionally complete foods for special medical purposes for children aged 1 to 10 years approved and registered by the State Administration for Market Regulation were examined and analyzed based on their label instructions. The results showed that there were no significant differences in the distribution of label values of protein, fat, or carbohydrates between different nutritionally complete food products. The average energy supply ratios of the three nutrients were 13.5%, 33.0%, and 53.5%, respectively, which were all within the appropriate range. The average label value of protein was 0.79 g/100 kJ, and the proportion of high-quality protein was 100%. The average energy supply ratios of linoleic acid and α-linolenic acid were 4.5% and 0.9%, respectively, which were significantly higher than the levels defined in the General rules of food for special medical purposes (GB 29922-2013). The vitamin and mineral label values of most products were equal to or up to 200% higher than the lower limit specified in GB 29922-2013. Optional ingredients such as dietary fiber, choline, and taurine were frequently used without the addition of fluoride or nucleotides. The most frequently used sources of protein, fat, and carbohydrate were whey protein, medium chain triglycerides, and maltodextrin, respectively.

Research Progress on the Oxidation Mechanism of Infant Formula and Methods for the Determination of Its Peroxide Value

BI Tingting, WEI Keyan, HU Mingyan, TIAN Hongyun, WANG Guanqun, WANG Wente, FAN Li, ZHANG Haihong, TI Jingliang

2025, 48(2):  54-59.  DOI: 10.7506/rykxyjs1671-5187-20240708-053

Asbtract ( )   HTML ( )   PDF (1604KB) ( )  

Related Articles | Metrics

Infant formula generally contains 25%–30% fat content. Unsaturated fatty acids, such as linoleic acid, linolenic acid, docosahexaenoic acid, arachidonic acid, and eicosapentaenoic acid, are often added to infant formula in order to ensure its nutritional adequacy. There is a membrane structure composed of whey protein-casein complexes on the surface of fat globules in infant formula, which leads to the accumulation of a fat layer on the surface of milk powder particles. This structure makes the oil in milk powder concentrate on the surface, which increases the chance of contact with oxygen and water, making the oil easier to oxidize and hydrolyze. During processing and storage, infant formula is susceptible to oxygen, metal ions and other fat oxidation reaction conditions, leading to the deterioration of product quality. In this paper, the fatty acid composition, the structural characteristics of fat globules, and the mechanism of fat redox reaction in infant formula are reviewed, and the different fat extraction methods and analytical methods used to determine the peroxide value of infant formula are summarized and evaluated. This review hopes to provide a theoretical basis for maintaining the quality and safety of infant formula milk powder during processing, storage, and marketing.

Research Progress on the Application of Whey Protein Powders in Foods for Special Medical Purposes

GENG Xue, WANG Bin, LUO Xiaoju, LIU Yue

2025, 48(2):  60-65.  DOI: 10.7506/rykxyjs1671-5187-20241210-104

Asbtract ( )   HTML ( )   PDF (2139KB) ( )  

Related Articles | Metrics

At present, China has approved 100 kinds of foods containing proteins for special medical purposes, including nutritionally complete formulas, specific nutritionally complete formulas, protein modules, and liquid formulas. Eighty-four percent of them are produced using whey protein as the protein source. This review examines these food formulations, focusing on the application of whey protein powders in them. Based on current regulatory requirements and the characteristics of whey protein, we discuss future prospects for the application of whey protein powders in foods for special medical purposes. This review provides support for the research and development of foods for special medical purposes (FSMP).