Defining the Glycan composition of alternative milk type products
Date
2023-10-31
Authors
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Publisher
Saudi Digital Library
Abstract
The demand for alternative milk-type products has increased substantially over the past
five years due to the distribution of lactose and protein allergies that are present in cow's milk,
making it vital to unearth an alternative that offers similar benefits to cow's milk without the
associated issues. There are several varieties of alternative milk-type products on the market, for
instance almond milk, oat milk and cashew milk. Some of the manufacturer’s labelling claims
that glycans provide significant health benefits in terms of improved digestion. As an example,
many brands assert that oat milk is rich in fibre, free of lactose and a source of calcium. Thus, the
aim of this project is to define the true glycan (polysaccharide) profile of all the alternative
milk-type products available on the market using high-throughput microarray technology and
explain their benefits pertaining to human health. The methods included buying and cataloguing
fifty different alternative milk types; preparing and printing samples by microarray robot and
probing the samples with primary and secondary antibodies, and lastly, analysing and presenting
the data. The result is presented as a heat map for nine classes of polysaccharides. The heat map
illustrates that all plant-based milk had heteromannan, pectic and arabinogalactan-protein (AGP)
classes. Callose and the glucuronoxylan class confirmed a high presence in most oat milk
samples. There was no binding with the fructose or the heteroxylan classes in all samples. It is
worth mentioning that this study could be completed in future research to test more ingredients,
such as gluten, lactose or gum.
Description
Between dilutions 2 (Figure 6) and 1 (Figure 5), there was an obvious drop in binding. This may
possibly be due to the alternative milk losing more polysaccharide each time the sample is
diluted, making antibody binding more challenging to detect. Samples 4 to 13 (Figure 7d)
confirmed that the oat milk had a high binding as regards callose (beta-glucan), despite the fact
they were made in contrasting ways and used different types of oat (whole oat, barista, no sugar,
unsweetened). However, they all had the same value with regards to human health benefits.
Numerous clinical trials have proved the considerable benefits of beta-glucan as an antibacterial,
anticancer, anti-diabetic and anti-hypercholesterolemic (Nourish by WebMD, 2022). The same
samples (4–13), attained the same result with LM28, which binds to the glucuronoxylan class,
presenting the glucronosyle residues of xylan (Figure 7g). According to Smith and Melrose
(2022), Xylan promotes beneficial symbiont microbes, for example
Bifidobacterium and Lactobacillus sp. in the human gut and maintains mucosal health and
immune function. Additionally, it prevents pro-inflammatory bacteria, such as Salmonella sp.
from colonising the gut and encourages the growth of Roseburia that enhances gut barrier
properties and lowers plasma lipid levels to lessen the pro-inflammatory effects of a high-fat diet.
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Almond milk, which includes samples 19 and 30, shows that the almond milk drink achieves a
different percentage for binding with pectic polysaccharide (Figure 7b). JIM 6
((1,5)-alpha-L-arabinan) followed by LM26 (branched (1,6-Gal)(1,4)-beta-D galactan) recorded
no binding. JIM2 (partially methylated homogalacturonan (Me-HG)), LM5 ((1,4)-β-D-galactan)
and LM6 ((1,5)-α-arabina) have a higher value between (1-43). Almond milk, oat milk and
coconut milk contain a high percentage of mannan (Figure 7e).
Keywords
Plant based milk, glycan, antibody, microarray robot, heat map