Yield and purity
The extraction method also affects the yield and the purity of produced β-glucans. Method 4 shows the highest yield (16.58%) calculated as the dry weight of extracted glucan/dry weight of yeast biomass.[24] In Method 2, the yield is 13.64% (dry weight of β-glucan/dry weight of yeast) and in Methods 3 and 5 the yield is similar (11.08±0.19% and 11.18%, respectively, calculated as the dry weight of extracted β-glucan/dry weight of yeast).[22, 23, 25] In Methods 7 and 8, the yield is calculated as the dry weight of extracted β-glucan/dry weight of dry yeast cell wall content.[27, 28] All methods, except for Methods 6 and 7 in which the purity is not referred to, show a high degree of purity (up to 90%), expressed with different ways (% glucose in β-glucan solids, % total carbohydrates, total β-glucan in S. cerevisiae/recovered β-glucan, ratio of mannan/glucan). The yield and the purity of extracted β-glucans for each method and the optimization of each extraction step are reviewed in Table 3.