One potential strategy for biorefining of chitin-rich biomass entails enzymatic saccharification, which, so far, has been scarcely explored. Here, saccharification of chitin was explored using response surface methodology available in the MODDE®10 software, to develop optimal cocktails of five mono-component enzymes from Serratia marcescens, three chitinases, SmChiA, SmChiB, SmChiC, a lytic polysaccharide monooxygenase, SmLPMO10A (or "CBP21"), and a beta-N-acetylhexosaminidase, SmCHB ("chitobiase"). These five enzymes were recombinantly produced in Escherichia coli. For both shrimp and crab chitins, SmChiA was the most abundant (40% and 38%, respectively) in the optimized cocktails, whereas SmChiB, SmChiC and SmLPMO10A were present at 30% and 26%, 15% and 23%, and 3% and 2%, respectively. Saccharification yields were 70%-75%, whereas a "minimal" cocktail of SmChiA and SmCHB gave only 40% saccharification. These results show that enzymatic saccharification of chitin requires multiple enzyme activities applied at dosages similar to those used for saccharification of cellulose.
Black walnut (Juglans nigra L.) is a North American hardwood tree valued for producing nuts and wood. Black walnut cultivars were evaluated by a trained panel over 2 growing seasons to determine the seasonal variation in the sensory profile. Results showed that cultivars were significantly different on 3 appearance (skin color, nutmeat color, and kernel roughness), 1 aroma (black walnut ID), 5 flavor (black walnut ID, banana-like, piny, rancid, and overall nutty), and 2 texture attributes (surface roughness and hardness). These profiles were compared to results collected in 2011 to determine differences between growing seasons. Results showed 4 flavor attributes (black walnut ID, overall nutty, fruity-dark and rancid) had an interaction effect of year and cultivar, while 6 attributes (brown, caramelized, floral/fruity, piny, musty/dusty, and oily) showed a main effect of year. In general, flavor attributes had higher intensities in 2011 than in 2013. These results suggest that seasonal variation may influence flavor profile more than cultivar. Thus, using samples from only 1 growing season when testing agricultural products may not provide adequate information for the long term.
The successful application of these isolates in successive two-step fermentation of brown crab shell waste to extract chitin means with further research into optimization and scale up, this chitin extraction process may be applied on an industrial scale and provide further commercial value from brown crab shell waste.
Summary
The objective of this study was to determine the sensory characteristics and consumer acceptance of gelato made with six black walnut cultivars: Davidson, Emma K, Football, Pounds, Sparks 127, and Vandersloot. The descriptive sensory panel found that black walnut ID, overall nutty and sour (P ≤ 0.05) attributes were different among gelato samples. The gelato samples were evaluated by 103 consumers for overall liking. Three clusters of consumers were found: one cluster of consumers (n = 29) liked milder black walnut flavour, while another (n = 20) liked more intense black walnut and overall nutty flavour. The third cluster of consumers (n = 54) liked all of the gelato samples. Consumer variation seeking tendency information was also collected. No significant differences in overall liking between the different types of variety seeking consumers. Gelati made with Pounds and Sparks 127 cultivars were accepted by all consumers indicating that these may be good cultivars to include in novel consumer products.
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