Comparative study of sugar extraction procedures forHPLCanalysis and proposal of an ethanolic extraction method for plant‐based high‐protein ingredients

Abstract

BACKGROUND:The increasing importance of plant-based proteins in the food sector makes a reliable compositional analysis of plant-based high-protein ingredients a necessity. Specifically, the quantification of short-chain carbohydrates is relevant for multiple areas, including food product development, food labelling and fundamental food chemistry and food technology research. Commonly used extraction procedures for subsequent high-performance liquid chromatographic separation and quantification of short-chain carbohydrates have been discussed controversially regarding a range of complications that can potentially lead to inaccurate sugar determination. The present study compares the sugar levels in wheat flour and wholemeal wheat flour determined with different aqueous and ethanolic extraction procedures. These procedures included measures to prevent enzyme activity and microbial growth, which represent two of the most relevant challenges in sugar extraction from food samples. RESULTS: Differences in sugar levels (sum of sucrose/maltose, glucose and fructose) as high as 1.8% dry matter (wheat flour) were observed between the employed extraction procedures. Ethanolic extraction (80% ethanol in ultrapure water) with the use of the antimicrobial agent sodium azide but without Carrez clarification was identified as most promising for sugar determination in plant-based high-protein ingredients.CONCLUSION: A screening of high-protein ingredients derived from cereals (wheat gluten), pseudocereals (quinoa, amaranth, buckwheat) and legumes (soy, pea, lupin, lentil, carob, chickpea, faba bean) concerning their levels of sucrose, maltose, glucose and fructose confirmed the applicability of the chosen extraction procedure.

Determination of Nutritional and Biochemical Composition of Selected Pleurotus spps.

“…The solid residues were concentrated at 40°C, diluted in water to a final volume of 5 mL, filtered using a disposable 0.22 m LC filter disc, and then put into an injection vial. This is just similar to that explained in [ 14 ].…”

“…With a final concentration of 100 mg/mL, a stock standard mixture of mannitol, trehalose, and arabinose was synthesized in water. As an internal standard (IS), fructose was produced as a stock solution in water at a concentration of 25 mg/mL and stored at -20°C [ 14 ].…”

“…By using chromatographic comparisons with actual standards, the components were identified. According to [ 14 ], the HPLC analysis' linearity and sensitivity were determined, and the method's instrument precision and accuracy were used to validate it.…”

“…Mushrooms have enormous nutraceutical properties like the treatment of cancer and the immune system [ 13 ]. Mushrooms help in decreasing the rate of diseases like stroke, Parkinson's disease, and hypertension as well as act as a cholesterol-lowering agent and antibacterial compound [ 14 ].…”

PROTEIN2FOOD – pioneering crops and food for future generations

“…The project aimed to (i) develop innovative, cost‐effective, and resource‐efficient food crops that are high in protein, with a positive impact on human health, the environment, and biodiversity; (ii) significantly enhance the quality and quantity of proteins from selected seed crops (quinoa, amaranth, and buckwheat) and grain legumes (lupin, faba bean, chickpea, and lentil), by using a multidisciplinary approach, involving genetics, agronomy, and food‐processing engineering, as well as sensory, socio‐economic and environmental assessment; (iii) to gain a better understanding of (i) genetic mechanisms that drive protein formation and accumulation in seeds; (ii) plant resilience against biotic and abiotic stresses (pests and environmental factors); (iii) protein interactions with other food components and their sensory consequences in the final food products. In this Special Issue of the Journal of the Science of Food and Agriculture , we gathered relevant papers 1‐13 covering fundamental and applied research aspects addressed by the multidisciplinary teams of the PROTEIN2FOOD project to bring added value to the plant‐protein food chain.…”