Comparison between barley malt protein quantification methods

Abstract

Brazil imports about 60% of all the malt used by the brewing industry which is spread throughout the country. Even though it is an agricultural country, only a small portion of the barley production has the characteristics to produce barley malt for brewing. Seeking supply to the ever-growing demand and reducing the dependency on other countries and logistic costs, malting industries and genetic enhancement companies endeavor to adapt barley to the Brazilian Savannah conditions. For the barley to be malted, it is crucial to develop cultivars with the necessary malting qualities and adapted to the region and with good yield. Considering the importance of protein to the brewing process, four protein quantification methods were compared: combustion methods-carbon, hydrogen and nitrogen elemental analysis and Dumas-and digestion ones-Kjeldahl and flux injection analysis (FIA). The methodologies tested showed good correlations (higher than 0.881) and variations were associated with matrix complexity. All protein quantification methods were satisfactory from an agronomic perspective. Yet, we recommend the combustion ones as they generate fewer residues and results are ready in up to 6 minutes. Therefore, they are the most suited for barley and malt analysis considering lab routine.

Quality attributes for barley malt: “The backbone of beer”

“…For all‐malt beers, protein values exceeding 12% is the indication of haze formation in beer or present mash runoff problems (Deme et al., 2020). Taking into consideration of the significance of protein in the brewing process, four protein quantification methods, that are, combustion methods—carbon, hydrogen, and nitrogen elemental analysis and Dumas and digestion ones— Kjeldahl and flux injection analysis—were compared and concluded that all quantification methods are valid for determining protein content in barley (Cenci et al., 2020). However, the authors suggested the usage of combustion methods due to their low health and environment hazards and the rapid analysis which takes up to 6 min.…”

Novel hollow-electrode glow discharge mass spectrometry for the quantitative analysis of protein content in food

“…[9][10][11] At present, there are mainly two methods for detecting protein content in food, namely the Dumas combustion nitrogen method and the Kjeldahl nitrogen method. 12,13 Dumas combustion nitrogen determination: this method uses high-purity oxygen to burn the sample in a hightemperature environment from 900 °C to 1000 °C, producing nitrogen oxides. Other products such as carbon dioxide, sulfur dioxide and water are absorbed by the adsorbent, while nitrogen oxides are reduced to nitrogen gas by tungsten and copper in a reduction tube, and the nitrogen gas is carried by the carrier gas into the thermal conductivity detector to calculate the nitrogen content in the sample.…”

“…9–11 At present, there are mainly two methods for detecting protein content in food, namely the Dumas combustion nitrogen method and the Kjeldahl nitrogen method. 12,13…”

A rapid identification method of rice protein in rice starch based on synchronous fluorescence spectroscopy

“…There are many methods for protein detection, the most commonly used are Kjeldahl method, Lowry method, Dumas method and Bradford method (Bonjoch & Tamayo, 2001;Jiang et al, 2013). It is recommended the use of combustion methods for their lower production of environment-and health-hazardous residues and the rapid analysis (Cenci et al, 2021) .However, the procedure is tedious, the detection takes an extended period of time, and also requires the consumption of large volumes of reagents. Beyond that, Tedious operation also cause damage to the product during the detection (Zhongfu et al, 2015).…”