Comparison of Various Preparation Methods for Determination of Organic Acids in Fruit Vinegars with a Simple Ion-Exclusion Liquid Chromatography

Abstract

An ion-exclusion liquid chromatography with mobile phase 0.005 mol L −1 H 2 SO 4 and step flow rate gradient (0.2 mL min −1 in the first 40 min and 0.5 mL min −1 from 41 to 60 min) was used to determine 20 organic acids simultaneously at 17°C within 51 min. The peak resolutions (Rs) were 0.45∼3.02 and separation factors (α) were all higher than 1. Impurities in fruit vinegar executed with direct injection or C18 cartridge clean-up for analysis would influence the glutaric and oxalic acid measurement; however, SAX cartridge extraction could reduce the interferences (organic acid recoveries were 93.93∼99.98%). Acetic, ascorbic, citric, malic, and malonic acids were the major organic acids in fruit vinegars (apple, apple sparkling, plum, cranberry, and grape).

Effects of supplementing an active dry yeast product on rumen microbial community composition and on subsequent rumen fermentation of lactating cows in the mid‐to‐late lactation period

“…Concentrations of organic acids in ruminal fluid were quantified by high‐performance liquid chromatography (Alliance HPLC system; Waters, Milford, MA, USA) using ion‐exclusion separation in accordance with Lin et al . (), and NH 3 determined by the salicylate‐nitroprusside‐hypochlorite method using a flow injection analyzer. Concentrations of milk fat, milk protein, milk solid‐not‐fat, somatic cells and milk urea nitrogen were determined using an automatic analyzer at each experimental institute.…”

Screening of traditional South African leafy vegetables for specific anti-nutritional factors before and after processing

“…Traditional leafy vegetables are inexpensive and easily accessible (Dmotoso, 2006). Traditional leafy vegetables are also easy to cook, provide roughage and are rich in vitamins and minerals (Lin et al, 2011). Traditional leafy vegetables grow wildly, do not require formal cultivation and can provide high nutrition for poor communities where malnutrition is rife (World Health Drganization, 1982).…”

Environmentally‐Friendly Lithium Recycling From a Spent Organic Li‐Ion Battery

“…[31] Malonic acid 2 is a natural but toxic compound that can be found in fermented fruits or fruit vinegars, [32] but it is especially abundant in alfalfa, [33] one of the most cultivated forage legumes in the world. For instance, dilithium trans-trans benzenediacrylate 1 could be synthesized through a Doebner modification of the Knoevenagel condensation from malonic acid 2 and terephthalaldehyde 3 (Scheme 1).…”

“…For instance, dilithium trans-trans benzenediacrylate 1 could be synthesized through a Doebner modification of the Knoevenagel condensation from malonic acid 2 and terephthalaldehyde 3 (Scheme 1). [31] Malonic acid 2 is a natural but toxic compound that can be found in fermented fruits or fruit vinegars, [32] but it is especially abundant in alfalfa, [33] one of the most cultivated forage legumes in the world. Terephthalaldehyde 3 can be prepared through a reduction reaction from terephthalic acid, [34] an important monomer for thermoplastic polymers.…”