ABSTRACT
This study investigates the contamination of cow milk with aluminum (Al) and its potential health implications, particularly for children. Cow milk samples were collected from both nonexposed and exposed areas in Sindh, based on the source of livestock drinking water (fresh canals and groundwater). An environmental friendly deep eutectic solvent (DES) was used with ultrasonic-assisted dispersive liquid-liquid microextraction (UDLLµE) to enrich trace amounts of Al in whey milk and water samples. The enriched samples were then analyzed using inductively coupled plasma optical emission spectrometry. Certified reference materials were employed to validate the methodology, and the experimental results exhibited acceptable conformity. The DES-based dispersive liquid-liquid microextraction method was environmental friendly, devoid of acids and oxidizing agents, and used safe and inexpensive components for routine trace metal analysis in diverse samples. The resulting data revealed that Al in whey milk samples was observed in the range of 31-45 %, corresponding to (160-270) µg L-1 and (700-1035) µg L-1 in nonexposed and exposed whole cow milk samples, respectively. Additionally, it was observed that milk boiling in Al utensil for 10-20 min enhanced the Al levels from 3 to 8% of its total contents in milk samples.
Subject(s)
Liquid Phase Microextraction , Milk , Child , Cattle , Animals , Humans , Solvents/chemistry , Milk/chemistry , Whey , Aluminum/analysis , Deep Eutectic Solvents , Liquid Phase Microextraction/methods , Limit of DetectionABSTRACT
Background: The information on official testing methods, or regulatory methods in Colombia to test whey in milk is limited; this restriction of information goes against the possibility of mitigating the risk of food fraud. Objectives: The validation of an HPLC method to determine casein glycomacropeptide (c-GMP), a protein that countries such as Brazil, Spain, and Ecuador have used as an indicator of raw milk adulteration with whey, was carried out. Methods: A 10mL sample of raw milk is precipitated with 24% TCA using ultrasound, a process followed by filtration. The collected fraction ensured the separation of c-GMP and then injected into the liquid chromatography. Results: A 30 minutes analysis allowed the determination of c-GMP with a retention time of 12.9 ± 0.5 minutes. The performance characteristics method in the validation exercise were: recovery percentage 99.97%, linearity R2> 0.95; % RSD accuracy <5.3%. Conclusion, the method exhibits desirable attributes for the intended purpose
Antecedentes: En Colombia la información de dominio público en metodologías de análisis de lactosuero en leche es limitada, restringiendo la posibilidad de acceder a ellas para mitigar el riesgo de fraude alimentario. Objetivos: Se realizó validación de un método por HPLC para determinar en leche cruda c-GMP, proteína usada como indicador de adulteración en países como Brasil y Ecuador. Metodos: Una muestra de 10mL de leche cruda es precipitada con TCA al 24% empleando ultrasonido, proceso seguido por filtración. La fracción recolectada aseguró la separación del c-GMP para luego inyectar al cromatógrafo líquido. Resultados: La determinación de c-GMP permitió el análisis en 30 minutos con tiempo de retención de 12,9 ± 0,5 minutos. Las características de desempeño del método en el ejercicio de validación fueron: porcentaje de recuperación 99,97%, linealidad R2>0,95; precisión %RSD< 5,3%. Conclusión: el método al final del ejercicio exhibe atributos para el fin previsto
Subject(s)
Humans , Chromatography, High Pressure Liquid , Caseins , Milk , FraudABSTRACT
This study aimed at investigating the proteomic adaptation of Lactobacillus plantarum strains. Cultivation of L. plantarum strains under food-like conditions (wheat flour hydrolyzed, whey milk, tomato juice) affected some metabolic traits (e.g., consumption of carbohydrates and synthesis of organic acids) compared to de Man, Rogosa and Sharpe (MRS) broth. The analysis of the fermentation profile showed that the highest number of carbon sources metabolized by L. plantarum strains was found using cells cultivated in media containing low concentration of glucose or no glucose at all. The proteomic maps of the strains were comparatively determined after growth on MRS broth and under food-like conditions. The amount of proteins depended on strain and, especially, on culture conditions. Proteins showing decreased or increased amounts under food-like conditions were identified using MALDI-TOF-MS/MS or LC-nano-ESI-MS/MS. Changes of the proteome concerned proteins that are involved in carbohydrate transport and metabolism, energy metabolism, Sec-dependent secretion system, stress response, nucleotide metabolism, regulation of nitrogen metabolism, and protein biosynthesis. A catabolic repression by glucose on carbohydrate transport and metabolism was also found. The characterization of the proteomes in response to changing environmental conditions could be useful to get L. plantarum strains adapted for specific applications. BIOLOGICAL SIGNIFICANCE: Microbial cell performance during food biotechnological processes has become one of the greatest concerns all over the world. L. plantarum is a lactic acid bacterium with a large industrial application for fermented foods or functional foods (e.g., probiotics). The present study compared the fermentation and proteomic profiling of L. plantarum strains during growth under food-like conditions and under optimal laboratory conditions (MRS broth). This study provides specific mechanisms of proteomic adaptation involved in the microbial performances (carbohydrates utilization, energy metabolism, stress resistance, etc.) affecting the main biotechnological tracts of L. plantarum strains. The finding of this study provides evidences that may be exploited to get strains adapted for specific applications in food biotechnology.
