No abstract

In this study, magnetic carbonaceous acids were synthesized by pyrolysis of the homogeneous mixtures of glucose and magnetic Fe3O4 nanoparticles, and subsequent sulfonation. The synthesis conditions were optimized to obtain a catalyst with both high acid density (0.75 mmol g−1) and strong magnetism [magnetic saturation, Ms = 19.5 Am2 kg−1]. The screened catalyst (C-SO3H/Fe3O4) was used to hydrolyze ball-milled cellulose in a microwave reactor with total reducing sugar (TRS) yield of 25.3% under the best conditions at 190 °C for 3.5 h. It was cycled for at least seven times with high catalyst recovery rate (92.8%), acid density (0.63 mmol g−1) and magnetism (Ms = 12.9 Am2 kg−1), as well as high TRS yield (20.1%) from the hydrolysis of ball-milled cellulose. The catalyst was further successfully tested for the hydrolysis of tropical biomass with high TRS and glucose yields of 79.8% and 58.3% for bagasse, 47.2% and 35.6% for Jatropha hulls, as well as 54.4% and 35.8% for Plukenetia hulls.

Frozen flour products refer to frozen food made from wheat and other cereals processed or cooked with other materials such as meat, poultry, vegetables, fruits, sugar, oil, and spices, including frozen dumplings, steamed buns, noodles, bread, etc. (Bhattacharya et al., 2003; Meziani et al., 2012). In recent years, with the rapid development of the food industry, large-scale branding, and chain operations have led to the industrialized development of Chinese traditional dough products (Wolt & Dappolonia, 1984). Therefore, frozen dough technology has become a hot topic in China's traditional fermented food system. Traditional preservation techniques for dough include low temperature (4°C) and freezing (−18°C). Products preserved using low-temperature storage (4°C) have a short shelf life, a narrow sales area, and quality and safety problems. Products in this form are limited to a small range of circulation. The freezing or freezing storage process had little influence on the physical and chemical properties of the raw starch in raw dough or flour products, therefore, the freeze-thaw stability of raw starch in frozen dough or flour products was better. Therefore, the deterioration of the quality of frozen dough or dough products was not primarily caused by starch (Esselink et al., 2003). Some studies indicated that mechanical damage of the dough tissue will be aggravated and the gluten protein network structure will be destroyed because of recrystallization during conventional freezing storage (−18°C). Finally, the quality of the frozen dough products