Simultaneous analysis of carbohydrates and organic acids by HPLC-DAD-RI for monitoring goat's milk yogurts fermentation

• Published in: Talanta (Oxford) 2016-05, Vol.152, p.162-170
• Main Authors: Costa, Marion Pereira da, Frasao, Beatriz da Silva, Lima, Bruno Reis Carneiro da Costa, Rodrigues, Bruna Leal, Junior, Carlos Adam Conte
• Format: Article
• Language: English
• Subjects: Animals; Bacteria; Carbohydrates; Carbohydrates - analysis; Carboxylic Acids - analysis; Chromatography, High Pressure Liquid - instrumentation; Cupuassu pulp; Detectors; Electrical Equipment and Supplies; Fermentation; Goats; Inulin; Lactic acid; Lactose; Limit of Detection; Milk; Milk - metabolism; Milk - microbiology; Organic acids; Probiotic; Probiotics; Refractometry; Reproducibility of Results; Validation; Yogurt - analysis; Yogurt - microbiology
• ISSN: 0039-9140; 1873-3573
• DOI: 10.1016/j.talanta.2016.01.061

During yogurt manufacture, the lactose fermentation and organic acid production can be used to monitor the fermentation process by starter cultures and probiotic bacteria. In the present work, a simple, sensitive and reproducible high-performance liquid chromatography with dual detectors, diode array detector and refractive index was validated by simultaneous analysis of carbohydrates and organic acids in goat milk yogurts. In addition, pH and bacterial analysis were performed. Separation of all the compounds was performed on an Aminex HPX-87H column (300×7.8mm, 9µm) utilizing a 3mmolL−1 sulfuric acid aqueous mobile phase under isocratic conditions. Lactose, glucose, galactose, citric, lactic and formic acids were used to evaluate the following performance parameters: selectivity, linearity, precision, limit of detection (LOD), limit of quantification (LOQ), decision limits (CCα), detection capabilities (CCβ), recovery and robustness. For the method application a six goat milk yogurts were elaborated: natural, probiotic, prebiotic, symbiotic, cupuassu fruit pulp, and probiotic with cupuassu fruit pulp. The validated method presented an excellent selectivity with no significant matrix effect, and a broad linear study range with coefficients of determination higher than 0.995. The relative standard deviation was lower than 10% under repeatability and within-laboratory reproducibility conditions for the studied analytes. The LOD of the method was defined from 0.001 to 0.003µgg−1, and the LOQ from 0.003 to 0.013µgg−1. The CCα was ranged from 0.032 to 0.943µgg−1, and the CCβ from 0.053 to 1.604µgg−1. The obtained recovery values were from 78% to 119%. In addition, the method exhibited an appropriate robustness for all parameter evaluated. Base in our data, it was concluded that the performance parameters demonstrated total method adequacy for the detection and quantification of carbohydrates and organic acids in goat milk yogurts. The application of the method was successfully applied to monitoring different goat milk yogurts during fermentation. [Display omitted] •HPLC-DAD-RI method was validated for carbohydrates and organic acids analysis.•Selectivity, linearity, precision, recovery, LOD, LOQ and robustness were adequate.•HPLC-method was able to detect and quantify carbohydrates and organic acids in yogurt.•Carbohydrates and organic acids were evaluated in different goat milk yogurt.•Cupuassu pulp addition reduces the fermentation time of goat milk yogurt.