Optimizing the Utilization of Gluten-Free Grains for the Production of Gluten-Free Beer
Restricted (Penn State Only)
- Author:
- Ledley, Andrew
- Graduate Program:
- Food Science
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- September 23, 2022
- Committee Members:
- Robert Roberts, Program Head/Chair
Ryan Elias, Dissertation Co-Advisor
Jeffrey Catchmark, Outside Unit & Field Member
Helene Hopfer, Major Field Member
Philip Jensen, Special Member
Darrell Cockburn, Chair & Dissertation Advisor - Keywords:
- beer
gluten-free beer
brewing
amylases
mashing
fermentable sugars
malt enzymes
starch hydrolysis
starch gelatinization
starch granules - Abstract:
- Celiac disease affects an estimated 1% of the global population, and symptoms are triggered by the consumption of gluten in sensitized individuals. Other gluten sensitivities exist but are poorly characterized or often under-diagnosed. It is estimated that the percentage of the global population who may have adverse reactions to gluten consumption, ranging from mild to extreme sensitivities, is much higher than the quoted figures for celiac disease. Gluten is a complex suite of proteins from the prolamin fraction of storage proteins in barley, wheat, and rye, meaning that foods or beverages that are produced from these cereals will also contain gluten. Beer is one such beverage that is traditionally produced from malted barley, though often will contain both wheat and rye as ingredients. Since beer is a gluten-containing beverage there is a portion of the population who cannot drink beer due to a celiac diagnosis, but likely a larger subset who unknowingly drink beer and have some adverse reactions, or who adhere to a gluten-free (GF) diet and avoid beer entirely. For these individuals then, there are very few true GF beer options, meaning the brewing industry is losing out on potential beer consumers by failing to provide a suitable alternative beer. Many brewers have recognized this opportunity but utilizing GF brewing ingredients is difficult when adapted to a traditional barley-centric processing framework. Much of the previous research on producing GF beers has centered on producing “traditional” barley beers then subjecting them to various treatments to reduce or remove gluten in hopes of reducing or removing the risk to gluten sensitive individuals. Unfortunately, although these treatments can be effective at reducing gluten, they do not ensure a barley beer is truly GF because the nature of gluten proteins and gluten sensitivities are very complex. As a result, these treated beers cannot be labelled as GF. Producing a GF beer that would be suitable for gluten sensitive individuals thus requires the usage of GF ingredients. Potential GF brewing ingredients include materials like millet, sorghum, teff, rice, corn, buckwheat, and various other starchy cereal-like food materials that have similar properties and usage in foods as barley, wheat, or rye, but lack gluten proteins. In previous studies that have investigated the usage of these alternative ingredients, used as malts in brewing, the brewing process is often reported to be more difficult. One of the main issues being that the enzymatic power of the alternative grains is far less than typically expected with modern barley malts. This enzymatic power, typically referred to as diastatic power, is a nonspecific test that assays a malt’s ability to produce fermentable sugars, which is the key objective of the mashing step in brewing. Despite some additional processing changes that will be required when utilizing alternative ingredients, many of these studies do not adequately address the way in which the alternative ingredients differ from barley. That is, they tend to utilize processing strategies optimized for barley without making the appropriate modifications for different ingredients. The purpose of this work is to determine in what ways the malts differ from barley, chiefly regarding enzyme activities, enzyme properties, and starch gelatinization, to develop improved processing strategies towards utilizing GF ingredients, with particular focus on the formation of fermentable sugars and amino acids, which are the main nutrients yeast require for fermentation. Much of this work centered on reevaluating the starch-enzyme mashing system to better under the conditions required for fermentable sugar and amino acid production to produce better worts that more closely resemble the characteristics brewers expect from barley. The central hypothesis of this work is that the different GF ingredients are not inherently limited brewing ingredients because they differ from barley, but that they can be effective brewing ingredients if appropriate mashing procedures are developed.