Formation and Degradation of Beta-casomorphins in Dairy Processing

Milk proteins including casein are sources of peptides with bioactivity. One of these peptides is beta-casomorphin (BCM) which belongs to a group of opioid peptides formed from b-casein variants. Beta-casomorphin 7 (BCM7) has been demonstrated to be enzymatically released from the A1 or B b-casein variant. Epidemiological evidence suggests the peptide BCM 7 is a risk factor for development of human diseases, including increased risk of type 1 diabetes and cardiovascular diseases but this has not been thoroughly substantiated by research studies. High performance liquid chromatography coupled to UV-Vis and mass spectrometry detection as well as enzyme–linked immunosorbent assay (ELISA) has been used to analyze BCMs in dairy products. BCMs have been detected in raw cow’s milk and human milk and a variety of commercial cheeses, but their presence has yet to be confirmed in commercial yoghurts. The finding that BCMs are present in cheese suggests they could also form in yoghurt, but be degraded during yoghurt processing. Whether BCMs do form in yoghurt and the amount of BCM forming or degrading at different processing steps needs further investigation and possibly will depend on the heat treatment and fermentation process used, but it remains an intriguing unknown

Application of ultra-high performance liquid chromatography coupled to high-resolution mass spectrometry (Orbitrap™) for the determination of beta-casein phenotypes in cow milk

The objective of this study was to determine the β-CN phenotypes in cow milk collected from HF and cross-bred HF dairy cattle in Phu Dong, Vietnam. In total, 85 samples of raw milk were collected from 85 individual cows. Beta-casein (β-CN) phenotypes in cow milk were determined using ultra-high performance liquid chromatography coupled to high resolution mass spectrometry (UHPLC-HRMS). The results showed that three β-CN variants A1, A2 and I were detected and identified in the milk samples. Five β-CN phenotypes A1A1, A1A2, A1I, A2A2 and A2I were found with percentages of 0.035, 0.400, 0.059, 0.482 and 0.024, respectively. The higher proportion of β-CN phenotype A2A2 compared to other phenotypes was expected because of changes in dairy cow breeding in Phu Dong, Vietnam

Release of beta-casomorphins during in-vitro gastrointestinal digestion of reconstituted milk after heat treatment

© 2020 Elsevier Ltd This study assessed the impact of heat treatment on beta-casomorphin 5 (β-CM5) and beta-casomorphin 7 (β-CM7) after in-vitro gastrointestinal digestion of milk representing beta-casein (β-CN) A1A1, A2A2 and A2I phenotype. After heat treatment at 73 °C/20 s, 85 °C/5 min and 121 °C/12 min, milk samples were subjected to in-vitro gastrointestinal digestion. β-CM5/7 were analysed using ultra high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) and further confirmed using ultra high-performance liquid chromatography-high resolution accurate mass Orbitrap™ mass spectrometry (UHPL-HRMS). β-CM5 was not released after in-vitro gastrointestinal digestion of all heated milk. Similarly, β-CM7 was not released in all milk with β-CN A2A2 phenotype. However, this peptide level ranged from 127.25 to 198.10 ng/mL (4.94–7.70 ng/mg protein) in heated milk with β-CN A1A1 phenotype, whereas it was released at much lower levels ranging from 19.35 to 24.50 ng/mL (0.71–0.91 ng/mg protein) in heated milk with β-CN A2I phenotype

Identification and quantification of beta-casomorphin peptides naturally yielded in raw milk by liquid chromatography-tandem mass spectrometry

Beta-casomorphin peptides including beta-casomorphin 5 (β-CM5) and beta-casomorphin 7 (β-CM7) in raw cow milk were analyzed using a liquid chromatography-tandem mass spectrometry (LC-MS/MS). Milk samples were acidified with HCl followed by centrifuged and cleaned-up using solid-phase extraction (SPE). The eluents were evaporated to dryness and subsequently reconstituted with methanol. Limits of detection (LOD) were 0.32 ng/g for β-CM5 and 0.24 ng/g for β-CM7 and limits of quantification (LOQ) were 1.06 ng/g and 0.69 ng/g for β-CM5 and β-CM7, respectively. Recoveries ranged from 89.7% to 99.4% for β-CM5 and from 96.3% to 98.9% for β-CM7. Intra-day precision was ranged between 7.3% and 22.7% for β-CM5; and 4.5% and 7.3% for β-CM7, meanwhile inter-day precision resulted 7.3%–16.5% for β-CM5 and 9.3%–12.8% for β-CM7. The concentration of β-CM5/7 was analyzed in different milk samples. β-CM7 was detected in 21 out of 30 samples and ranged from 0.76 to 8.41 ng/g milk, while β-CM5 was unequivocally identified in 3 samples, its concentration was 0.4–0.64 ng/g. This is the first report to describe the natural occurrence of β-CM5/7 in raw milk using LC-MS/MS. The present study provides evidence of β-CMs, especially β-CM7 that can be released in raw milk from different breeds

The impact of oat quality on white salted noodles containing oat flour

This research compared the physicochemical properties of six milling oat cultivars from Western Australia over two growing seasons (2011 and 2012). Variations among the cultivars in physicochemical properties, particularly β-glucan content, were assessed to determine their suitability for incorporation into white salted noodles at a level of 30% of the flour component. The average across six oat cultivars grown in 2012 was significantly higher (P 100 µm) in comparison with the average across the same oat cultivars grown in 2011.The year of cultivation by cultivar interaction was significant (P < 0.05) for ash content, protein content, β-glucan content, starch damage, and particle size. Oat cultivar Mitika had the highest peak viscosity for 100% oat flour (whole groat) and 30% oat–wheat (OW) flour blend, which may be owing to lower amylose percentage, high protein content, and greater volume of smaller particles. The effect of growing season had greater impact on OW noodle firmness than the genetic effect of cultivars. The eating and cooking quality attributes of OW noodles, such as color, color stability, firmness, and cooking solid loss were superior for those incorporated with 2012 oat flour (whole groat) compared with 2011 oat flour. Among the six oat cultivars, Williams produced noodles with poor cooking and eating quality, and Mitika was easier to handle during processing and produced noodles with superior brightness and color stability in comparison with other oat cultivars evaluated