Free Amino Nitrogen Research Articles

The effect of germination time on malt quality of six sorghum (Sorghum bicolor) varieties grown at Melkassa, Ethiopia

The effect of germination time (48, 96 and 144 h) on malt quality of six sorghum varieties was investigated to determine the potential of grain sorghum cultivars in the local brewery industry. Six sorghum varieties (Gambella 1107, Macia, Meko, Red-Swazi, Teshale and 76 T1#23) were evaluated in a randomized complete block design with three replications. The results showed that both germination time and variety had a significant effect (p ≤ 0.05) on sorghum malt quality. The hectolitre weight (kg hL−1 at 12.5% moisture), germination energy (%), crude protein (%) and flour starch amylose content (%) were: 75.8–82.9, 96–99, 7.0 − 11.9 and 16.0 − 23.0, respectively. The sorghum malt diastatic power (DP, °L), free amino nitrogen (FAN, mg L−1), hot water extract (HWE, %) and malting loss (%) were: 18.96 − 31.39, 185.67 − 343.29, 41.85 − 85.08 and 8.68 − 27.56, respectively. Malting loss, HWE and FAN increased with germination time. The DP increased as the germination duration increased from 48 to 96 h, but the difference between 96 and 144 h was not significant. Considering the excessive malting loss and marginal increase in HWE beyond 96 h, this study suggests that the optimum malting duration would be around 96 h. Among the varieties tested, Teshale and Gambella 1107 produced the better malt quality. Copyright © 2012 The Institute of Brewing & Distilling

Relationship between Kolbach index and other quality parameters of wheat malt

In order to determine suitable Kolbach indices in wheat malting, the relationships between the Kolbach index and other quality parameters in wheat malt were studied. Eight white wheat malts with different Kolbach indices (31.4, 33.1, 37.0, 37.6, 39.5, 40.7, 42.8 and 45.5%) from the same wheat variety were prepared. The increase ratio of the ALSP (albumins and other soluble proteins) and the decrease ratio of the glutenins were found to have a significant positive correlation with the Kolbach index, and the corresponding r-values were 0.883 and 0.975 (p < 0.01). The ALSP of the wheat malts had a positive correlation with chromaticity, extract, free amino nitrogen (FAN), viscosity, acidity, xylan glycosidase activity, endo-β-1,4-xylanase activity and malting loss (p < 0.05). When the Kolbach indices were 31.4, 33.1, 37.0, 37.6 and 39.5%, there was a positive correlation between the soluble xylan and the viscosity, and the r-value was 0.888 (p < 0.05). Comparing the malts, it could be concluded that, for this particular wheat variety, when the Kolbach index was 39.5%, the wheat malts exhibited the best characteristics; the extract was 81.98%, the FAN content was 166.03 mg per 100 mg, the saccharifying power was 496.72 WK, the viscosity was 1.61 cP, and the saccharification time was 6 min. Copyright © 2012 The Institute of Brewing & Distilling

Addition of protease during starch liquefaction affects free amino nitrogen, fusel alcohols and ethanol production of fermented maize and whole and decorticated sorghum mashes

The aim of this research was to study the effect of the dual treatment of sorghum decortication and protease addition during liquefaction with α-amylase, on the concentration of free amino nitrogen (FAN), fusel alcohols and ethanol during yeast fermentation. A bifactorial experiment was designed to revise the differences among grains (maize, whole and 9.7% decorticated sorghum) and the effectiveness of protease addition during liquefaction. The decorticated sorghum was more susceptible to protein hydrolysis compared to the whole kernel sorghum due to its lower fiber content. The protease improved the levels of FAN approximately to 60% and 30% in the maize and sorghum mashes, respectively. The maize mash contained the highest amount of FAN followed by the decorticated and whole sorghum mashes. The protease treatment improved the fusel alcohol concentration in both sorghum beers and did not affect ethanol concentration in the maize mash. Both sorghum decortication and protease addition during liquefaction are therefore recommended treatments to obtain mashes with a higher FAN level. The decorticated protease-treated sorghum mashes yielded higher amounts of ethanol compared to the maize treatments and produced the maximum ethanol after only 20h of fermentation. This research proved that a positive synergistic effect on FAN concentration, fusel alcohols and bioethanol yields can be achieved through the proposed proceeding of sorghum decortication and protease addition.

Effect of Germination Temperatures on Proteolysis of the Gluten-Free Grains Sorghum and Millet during Malting and Mashing

Our study showed that sorghum and millet followed a similar pattern of changes when they were malted under similar conditions. When the malt from these cereals was mashed, both cereal types produced wide spectra of substrates (sugars and amino acids) that are required for yeast fermentation when malted at either lower or higher temperatures. At the germination temperatures of 20, 25, and 30 °C used in malting both cereal types, production of reducing sugars and that of free amino nitrogen (FAN) were similar. This is an important quality attribute for both cereals because it implies that variation in temperature during the malting of sorghum and millet, especially when malting temperature is difficult to control, and also reflecting temperature variations, experienced in different countries, will not have an adverse effect on the production and release of amino acids and sugars required by yeast during fermentation. Such consistency in the availability of yeast food (substrates) for metabolism during fermentation when sorghum and millet are malted at various temperatures is likely to reduce processing issues when their malts are used for brewing. Although sorghum has gained wide application in the brewing industry, and has been used extensively in brewing gluten-free beer on industrial scale, this is not the case with millet. The work described here provides novel information regarding the potential of millet for brewing. When both cereals were malted, the results obtained for millet in this study followed patterns similar to those of sorghum. This suggests that millet, in terms of sugars and amino acids, can play a role similar to that of sorghum in the brewing industry. This further suggests that millet, like sorghum, would be a good raw material for brewing gluten-free beer. Inclusion of millet as a brewing raw material will increase the availability of suitable materials (raw material sustainability) for use in the production of gluten-free beer, beverages, and other products. The availability of wider range of raw materials will not only help to reduce costs of beer production, but by extension, the benefit of reduced cost of production can be gained by consumers of gluten-free beer as the product would be cheaper and more widely available.

Production of multiple extracellular enzyme activities by novel submerged culture of Aspergillus kawachii for ethanol production from raw cassava flour

Cassava is a starch-containing root crop that is widely used as a raw material in a variety of industrial applications, most recently in the production of fuel ethanol. In the present study, ethanol production from raw (uncooked) cassava flour by simultaneous saccharification and fermentation (SSF) using a preparation consisting of multiple enzyme activities from Aspergillus kawachii FS005 was investigated. The multi-activity preparation was obtained from a novel submerged fermentation broth of A. kawachii FS005 grown on unmilled crude barley as a carbon source. The preparation was found to consist of glucoamylase, acid-stable α-amylase, acid carboxypeptidase, acid protease, cellulase and xylanase activities, and exhibited glucose and free amino nitrogen (FAN) production rates of 37.7 and 118.7mg/l/h, respectively, during A. kawachii FS005-mediated saccharification of uncooked raw cassava flour. Ethanol production from 18.2% (w/v) dry uncooked solids of raw cassava flour by SSF with the multi-activity enzyme preparation yielded 9.0% (v/v) of ethanol and 92.3% fermentation efficiency. A feasibility study for ethanol production by SSF with a two-step mash using raw cassava flour and the multi-activity enzyme preparation manufactured on-site was verified on a pilot plant scale. The enzyme preparation obtained from the A. kawachii FS005 culture broth exhibited glucose and FAN production rates of 41.1 and 135.5mg/l/h, respectively. SSF performed in a mash volume of about 1,612l containing 20.6% (w/v) dry raw cassava solids and 106l of on-site manufactured A. kawachii FS005 culture broth yielded 10.3% (v/v) ethanol and a fermentation efficiency of 92.7%.

Wort Free Amino Nitrogen Analysis Adapted to a Microplate Format

The standard method for determining wort free amino nitrogen content is a long-established but now relatively outdated procedure, calling for the use of test tubes, marbles, several water baths (boiling and 20°C), manual sample transfers, and a conventional spectrophotometer. Currently, many malting quality laboratories avoid use of this cumbersome manual system by adopting automated chemistry analysis systems as their in-house standard method for wort free amino nitrogen analysis. Several recent papers have taken a somewhat different approach to measuring malting quality by adapting the basic analytical method to microtiter plates, microplate readers, and related instrumentation. This streamlines sample handling and increases sample capacity. However, results from the several free amino nitrogen methods published previously have not been directly compared. In this study, we analyzed several malts using the standard ASBC Wort-12 method, our standard Skalar segmented flow analysis chemistry system, and several variations of those two chemistries in microplate formats to compare the results obtained by the different analysis systems. Among these methods, the results from the manual ASBC Wort-12, the automated Skalar system, and a microplate-format assay based on the Skalar reagents agreed well. Surprisingly, however, direct adaptation of the Wort-12 reagents, times, and temperatures to the microplate format yielded inconsistent results. We examined a number of parameters in the microplate-format Wort-12 implementation but were unable to identify a single factor responsible for the divergence of results. From these results, we recommend adapting the chemistry from the Skalar segmented flow analysis system to a microplate format for analysis of wort free amino nitrogen content.

Utilisation of waste bread for fermentative succinic acid production

A novel biorefinery concept of utilising waste bread as a sole nutrient source for the production of a nutrient rich feedstock for the fermentative succinic acid production by Actinobacillus succinogenes has been developed. Waste bread was used in the solid-state fermentations of Aspergillus awamori and Aspergillus oryzae that produce enzyme complexes rich in amylolytic and proteolytic enzymes, respectively. The resulting fermentation solids were added directly to a bread suspension to generate a hydrolysate containing over 100g/L glucose and 490mg/L free amino nitrogen (FAN). A first-order kinetic model was used to describe the effect of initial bread mass ratio on glucose and FAN profiles. The bread hydrolysate was used as the sole feedstock for A. succinogenes fermentations, which led to the production of 47.3g/L succinic acid with a yield and productivity of 1.16g SA/g glucose and 1.12g/Lh. This corresponds to an overall yield of 0.55g succinic acid per g bread. This is the highest succinic acid yield compared from other food waste-derived media reported to date. The proposed process could be potentially utilised to transform no-value food waste into succinic acid, one of the future platform chemicals of a sustainable chemical industry.

Enhancing the value of nitrogen from rapeseed meal for microbial oil production

Rapeseed meal, a major byproduct of biodiesel production, has been used as a low-cost raw material for the production of a generic microbial feedstock through a consolidated bioconversion process. Various strategies were tested for the production of a novel fermentation medium, rich in free amino nitrogen (FAN): commercial enzymes (CEs) (2.7mgg−1 dry meal), liquid state fungal pre-treatment (LSF) using Aspergillus oryzae (4.6mgg−1), liquid state fungal pre-treatment followed by fungal autolysis (LSFA) (9.13mgg−1), liquid state pre-treatment using fungal enzymatic broth (EB) (2.1mgg−1), but the best strategy was a solid state fungal pre-treatment followed by fungal autolysis (34.5mgg−1).The bioavailability of the nitrogen sources in the novel medium was confirmed in fed-batch bioreactor studies, in which 82.3g dry cell L−1 of the oleaginous yeast Rhodosporidium toruloides Y4 was obtained with a lipid content of 48%. The dry cell weight obtained was higher than that obtained using conventional yeast extract, due to a higher total nitrogen content in the novel biomedium. The fatty acids obtained from the microbial oil were similar to those derived from rapeseed oil.

Fundamental study on the influence of Fusarium infection on quality and ultrastructure of barley malt

Barley infection with Fusarium species has been a long standing problem for the malting and brewing industries. In this study, we evaluate the impact of Fusarium culmorum infected raw barley on the final malt quality. Barley grains were infected for 5days at optimum fungal growth conditions. Grains were fully characterized and compared to standard barley grains. Due to fungal infection, germinative energy of infected barley grains decreased by 45%; its water sensitivity increased dramatically, and grains accumulated 199μg/kg of deoxynivalenol (DON). Barley grains were subsequently malted for 8days, fully characterized and compared to standard malt grains. Fungal growth behavior was evaluated during malting using a PCR-based assay and mycotoxins were measured using HPLC. Fungal biomass increased in grains, during all stages of malting. Infected malt accumulated 8-times its DON concentration during malting. Kernel ultrastructure was evaluated using scanning electron and confocal laser scanning microscopy. Infected malt grains were characterized by extreme structural proteolytic, (hemi)-cellulolytic and starch deterioration with increased friability and fragmentation. Infected grains had higher protease and β-glucanase activities, lower amylase activity, a greater proportion of free amino and soluble nitrogen, and a lower β-glucan content. Malt loss was over 27% higher in infected malt in comparison to the control. The results of this study revealed that 20% F. culmorum infected barley kernels lead to a significant reduction in malt quality as well as mycotoxin formation.

Fermentation characteristics of six probiotic strains in soymilk

Fermented soymilk was produced with the single culture of the six probiotic strains, including Lactobacillus casei Zhang, Bifidobacterium animalis ssp. lactis V9, Lactobacillus acidophilus NCFM, Lactobacillus rhamnosus GG, Bifidobacterium animalis Bb12, and Lactobacillus casei Shirota, and their fermentation characteristics were evaluated. The free amino nitrogen of soymilk fermented with the four probiotic strains, L. casei Zhang, B. animalis V9, L. acidophilus NCFM and L. rhamnosus GG, increased greatly. Significant increases in viable counts were observed among the six probiotic strains. All the fermented soymilk had a viable count above 8.69 log CFU/g at the end of fermentation, especially the four probiotic strains of L. casei Zhang, L. acidophilus NCFM, B. animalis Bb12, and L. casei Shirota, which were all over 9.00 log CFU/g. The content of glucose and fructose decreased for all the six probiotic strains after the fermentation, but along with the reduction in the content of stachyose and raffinose only for B. animalis V9, L. rhamnosus GG, and B. animalis Bb12. Our results indicated that the six probiotic strains can grow well and increase the contents of bioactive substances in soymilk, including γ-aminobutyric acid, vitamin B6, and total isoflavone aglycone, and deserves further research on utilization as potential starters for soymilk.

Impact of Mashing Conditions on Extract, its Fermentability, and the Levels of Wort Free Amino Nitrogen (FAN), β-Glucan, and Lipids

In a small-scale protocol, the mashing conditions used were found to have important influences on malt quality parameters, including extract, fermentability, and the levels of wort free amino nitrogen (FAN) and β-glucan. Understanding this relationship is important in determining and prioritizing malt components for malt quality assessment. The impact of mash-in temperatures of 62.5–75.0°C was assessed on a modernized small-scale mash program whose key parameters included grist milling at 0.7 mm by disc mill, addition of CaSO4 (0.3 mM) to water, grist/water ratio of 1:3, 60 min duration of the initial phase of mashing, and the completion of mashing at 74°C. Wort β-glucan and total protein levels were relatively stable, whereas FAN progressively decreased across the temperature range studied. Maximal fermentability was obtained at a mash-in temperature of 65°C. It was observed that malts containing the most thermostable β-amylase type, Sd2H, produced more fermentable worts and that these mashes maintained a greater degree of fermentability at the higher mash-in temperatures. At mash-in temperatures greater than 65°C, extract slowly decreased, whereas the level of wort total fatty acids increased substantially. The levels of linoleic (C18:2) and linolenic (C18:3) acids increased, whereas the level of palmitic (C16:0) and stearic (C18:0) acids declined at mash-in temperatures above 65°C. For yeast fermentation performance, C18:2 is a key nutritive component provided by wort. It was observed that malt samples from different barley varieties produced a range of levels of wort total fatty acid contents, although the greater proportion of this variation could be attributed to between sample variation at mash-in temperatures below 65°C. However, at mash-in temperatures above 65°C, the varietal sample became substantially more important in determining fatty acid content and composition. In both small-scale and commercial worts, wort boiling and trub removal reduced the level of wort fatty acids by up to 85 percentage points and increased the proportion of C16:0 while decreasing the proportion of C18:2. This effect of wort boiling was more variable with commercial brewery worts that were also more variable in the initial levels of total fatty acids and were not as consistent with respect to the extent of trub removal. In particular, the level and composition of wort fatty acids is well known to impact on yeast fermentation performance and generation of flavor-active esters. As such, brewers with a greater understanding of the determinants of the level and composition of the fatty acids in the wort from which they were brewing could potentially produce beer more efficiently and closer to their desired quality specifications.

Effect of Enzymes on the Quality of Beer/Wort Developed from Proportions of Sorghum Adjuncts

The effect of commercial enzymes on quality of wort developed from replacement of malted barley (100%) with sorghum as adjunct 50%, 60%, 70%, and 80% was investigated for pH, colour, filteration rate, extract asin, dry extract, viscosity, total soluble nitrogen and free amino nitrogen. The wort pH (5.6 - 6.0) is relatively stable with no significant changes at all levels of replacements. The colour is lighter with increment in proportion of the sorghum as it appears as colour diluents. Wort filteration rate is reduced with the sorghum replacement and the wort produced tends to be turbid which affects the utilization of the wort. The total soluble nitrogen and free amino nitrogen value increased with the use of commercial enzymes while the viscosity decreases with enzymes. The use of ceremix and cereflo have been found to be relatively more effective in the preparation of beer wort as observed for the result obtained in proportions of sorghum and malt barley. The use of high percentage sorghum as adjunct with commercial enzymes are found to be useful in production of high quality wort with low cost and profitability.

Genetic and Malt Quality Diversity of East Asian Two-Rowed Barley Accessions in Relationship to North American Malting Barley

Because of epidemics of Fusarium head blight (FHB; caused by Fusarium graminearum Schwabe [teleomorph Gibberella zeae (Schwein.) Petch]) in the northern Great Plains of the United States and Canada in the past two decades, malting barley breeders have been forced to use nonadapted barley (Hordeum vulgare L.) accessions as sources of FHB resistance. Many of the resistant accessions are from East Asia, and limited information is available on their genetic diversity and malt quality. The objectives of this study were to determine the genetic diversity among 30 East Asian accessions and two North American cultivars. Genetic diversity was based on 49 simple-sequence repeat markers. All accessions were tested for barley grain brightness; protein content; 1,000-kernel weight; malting loss; fine-grind malt extract; content of plump kernels, free amino nitrogen, soluble protein, and wort β-glucan; the Kolbach index (i.e., the ratio of malt soluble protein to malt total protein); α-amylase activity; diastatic power; wort color; and wort viscosity. A few accessions had equal quality compared with Harrington and Conlon barley for individual traits but not for all. Qing 2, Mokkei 93–78, and Nitakia 48 could be excellent sources for increased malt extract; Nitakia 48 is a possible source for low wort viscosity; and Mokkei 93–78 and Nitakia 48 are putative sources of low β-glucan content. The cluster analyses also implied that the malt quality of an accession cannot be predicted based on the country where it was developed.

No-Cook Process for Ethanol Production Using Indian Broken Rice and Pearl Millet

No-cook process using granular starch hydrolyzing enzyme (GSHE) was evaluated for Indian broken rice and pearl millet. One-factor-at-a-time optimization method was used in ethanol production to identify optimum concentration of GSHE, under yeast fermentation conditions using broken rice and pearl millet as fermentation feedstocks. An acid fungal protease at a concentration of 0.2 kg per metric ton of grain was used along with various dosages of GSHE under yeast fermentation conditions to degrade the grain proteins into free amino nitrogen for yeast growth. To measure the efficacy of GSHE to hydrolyze no-cook broken rice and pearl millet, the chemical composition, fermentation efficiency, and ethanol recovery were determined. In both feedstocks, fermentation efficiency and ethanol recovery obtained through single-step no-cook process were higher than conventional multistep high-temperature process, currently considered the ideal industrial process. Furthermore, the no-cook process can directly impact energy consumption through steam saving and reducing the water cooling capacity needs, compared to conventional high-temperature process.

Relationship between sensory attributes of bakasang (a traditional Indonesian fermented fish product) and its physicochemical properties

Quantitative descriptive analysis and physicochemical analysis were carried out to assess the relationship of the sensory attributes of bakasang (a traditional Indonesian fermented fish product) to its physicochemical properties. Pearson correlation analysis and partial least-squares regression (PLS-R) were used to analyze the data. Two PLS-R models were established for relating six physicochemical properties to 12 sensory attributes. The first PLS-R model indicated that salty, umami, bitter, and bitter aftertaste showed an excellent correlation to moisture content, water activity (aw), salt content, and free amino nitrogen. The second model indicated that sulphury meaty, overripe cheese, sweaty, and ammonia were positively correlated with the moisture content, aw, salt content, and total volatile bases. A microbiological quality test of this product indicated that it meets the standards of the Indonesian National Standard Quality of fish sauce.

Evaluation of Waxy Grain Sorghum for Ethanol Production

ABSTRACTThe objective of this research was to investigate the fermentation performance of waxy grain sorghum for ethanol production. Twenty‐five waxy grain sorghum varieties were evaluated with a laboratory dry‐grind procedure. Total starch and amylose contents were measured following colorimetric procedures. Total starch and amylose contents ranged from 65.4 to 76.3% and from 5.5 to 7.3%, respectively. Fermentation efficiencies were in the range of 86.0–92.2%, corresponding to ethanol yields of 2.61–3.03 gallons/bushel. The advantages of using waxy sorghums for ethanol production include easier gelatinization and low viscosity during liquefaction, higher starch and protein digestibility, higher free amino nitrogen (FAN) content, and shorter fermentation times. The results showed a strong linear relationship between FAN content and fermentation rate. Fermentation rate increased as FAN content increased, especially during the first 30 hr of fermentation (R2 = 0.90). Total starch content in distillers dried grains with solubles (DDGS) was less than 1% for all waxy varieties.

Bioconversion into ethanol of decorticated red sorghum (Sorghum bicolor L. Moench) supplemented with its phenolic extract or spent bran

The effect of extracted phenolics or spent bran added to decorticated red sorghum kernels during fuel ethanol production was studied and compared to maize and whole red and white sorghums. After liquefaction, free amino nitrogen ranged from 65 to 101 mg/l and at the end of saccharification all mashes had approx. 80 g glucose and 2-5 g maltose/100 g meal (dry basis). Saccharified worts were fermented giving 50-90 ml ethanol/l. The lowest fermentation efficiency (76%) was obtained in the white sorghum. Ethanol yields indicate that sorghum bran or its associated phenolics did not significantly affect the efficiency of the sequential steps involved in ethanol production. Red sorghum is a good alternative to maize to produce ethanol and the difference regarding white sorghum and maize was mainly due to endosperm protein structure and composition.

Susceptibility of Four Watermelon Cultivars to Infestation with Tetranyclws urticae Koch.

Experiments were conducted to estimate the susceptibility of four watermelon cultivars (Aswan, Daytona, Molokai and Giza-I) to infestation with Tetranychus urticae Koch and its population fluctuation during the two successive seasons, summer 2009 and early summer 20 I 0 at Qalubia Governorate. Aswan cultivar was the most highly susceptible recording average of 42.86 and 57.59 mite moving stages/leaf during the two successive seasons, respectively, followed by the moderately infested cultivars (Daytona) recording 28.10 and 39.75 mite individuals during the two seasons, respectively. The lowest infestation was recorded on Molokai and Giza-1 cultivars, being 19.18 & 25.90 for the former and 18.10 & 25.94 for the latter cultivar during the two successive seasons, respectively. Susceptibility of watermelon cultivars to infestation with T. urticae may be affected by plant leaf morphological structure and its chemical contents. The number of trichomes/cm2 leaf averaged 647.78, 744.44, 1111.11 and 1296.67 for Aswan, Daytona, Molokai and Giza-1 respectively, the less number of trichomes the more mite infestation. Positive relationships occurred between mite infestation levels and total amino acids, free amino acids, nitrogen and total soluble sugars in watermelon cultivars, while negative relationship found with tannins and nearly shown with total phenolic compounds, total flavonoids and total carotenes. Mite populations reached its peak during July and May in the first and second seasons, respectively, and infestation was lower in the first season than in the second, which might be due to early plantation.

Part I. The Use of Lactobacillus Plantarum Starter Cultures to Inhibit Rootlet Growth during Germination of Barley, Reducing Malting Loss, and its Influence on Malt Quality

The reduction of malting loss has been an ambition for many decades, with the aim to achieve higher yields in the malting process. Organic acids have been shown to possess restricting effects on rootlet growth if exceeding critical concentrations. Lactic acid bacteria are able to produce high amounts of organic acids. In the present study, the potential of a broad selection of Lactobacillus plantarum strains as starter cultures to reduce malting loss and their subsequent impact on malt quality were examined. Starter cultures were prepared in a modified de Man, Rogosa, and Sharp medium and added to the grain immediately after steeping. A chemically acidified solution was added to mimic the impact of acids produced by the L. plantarum strains on rootlet growth suppression. The bacterial fermentation broths of all L. plantarum strains tested reduced malting loss to a similar extent accompanied by lower friability values and increased β-glucan contents. Malting loss could be reduced from approx. 7.3 to 2.3%. Resteeping in the chemically acidified solution reduced malting loss to approx. 3.5%. In both cases, the reduction in malting loss was accompanied with lower enzyme activities, in particular α-amylase, limit dextrinase, and β-glucanase. Although the quality of malt produced with reduced malting loss was diminished compared with control malt, parameters such as soluble nitrogen, free amino nitrogen, β-glucan, and friability were still in a range that can be seen as sufficient for brewing purposes.

Determination of Free Amino Nitrogen in Wort by Segmented Flow Analysis

"Determination of Free Amino Nitrogen in Wort by Segmented Flow Analysis." Journal of the American Society of Brewing Chemists, 69(4), pp. 296–297FANSFA