Utilization of lignocellulosic materials for the production of value-added chemicals or biofuels generally requires a pretreatment process to overcome the recalcitrance of the plant biomass for further enzymatic hydrolysis and fermentation stages. Two of the most employed pretreatment processes are the ones that used dilute acid (DA) and alkaline (AL) catalyst providing specific effects on the physicochemical structure of the biomass such as high xylan and lignin removal for DA and AL, respectively. Another important effect that need to be studied is the use of a high solids pretreatment (≥15%) since offers many advantaged over lower solids loadings, including increased sugar and ethanol concentrations (in combination with a high solids saccharification) which will be reflected in lower capital costs, however this data is currently limited. In this study, several variables such as catalyst loading, retention time and solids loading, were studied using Response Surface Methodology (RSM) based on a factorial Central Composite Design (CCD) of DA and AL pretreatment on agave bagasse using a range of solids from 3 to 30% (w/w) to obtain optimal process conditions for each pretreatment. Subsequently enzymatic hydrolysis was performed using Novozymes Cellic CTec2 and HTec2 presented as total reducing sugar (TRS) yield. Pretreated biomass

The maturity of two selections of soursop (G1 and G2) from Nayarit, Mexico, was evaluated under environmental conditions at 22°C and refrigeration at 15°C stored for 6 and 8 days, respectively. Maximum CO₂and ethylene values were present on the fifth and sixth day. The fruits exposed at 15°C had a significantly lower weight loss (5%) and showed no chilling injury. The firmness of two selections decreased more than 90%. The concentration of TSS increased to 5.3 to 15°Brix, and the titratable acidity was higher for fruit stored at 22°C. The highest concentration of phenols was recorded on the fourth day of storage at 22°C. The enzymatic activity of PPO was increased from physiological ripening to consumption ripening for both treatments. The two selections stored at 22°C registered the highest level of PME activity at ripeness. Shelf life was increased by up to 8 days (4 days at 15°C plus 4 days at 22°C) without causing chilling injury or alterations in the ripening process of the fruits. No significant differences were observed between the two selections evaluated; postharvest handling was considered to be similar; however, it would be advisable to evaluate other technologies combined with refrigeration.

The development of new postharvest technologies, which prolong useful fruit life and are also biodegradable, has promoted the use of edible coatings, prepared based on polysaccharides obtained from nonconventional sources, such as the starch and pectin in banana fruits. The objective of this study was to evaluate the effects of coatings based on starch and pectin from ‘Pear’ banana, as well as chitosan applied to ‘Ataulfo’ mango fruit. Coverings with 1 % starch and others with 1 % pectin were applied by immersion to mango fruits at physiological maturity; fruits were then stored for 12 days at 10 ± 2°C, plus another 9 days at 22 ± 2°C. The assessed variables were: weight loss (%), color (L*, a*, b*), firmness (kgf∙cm-2), total soluble solids (°Brix), and titratable acidity (%). ‘Ataulfo’ mango fruits covered with starch from ‘Pear’ banana (Musa ABB) showed greater firmness (3.34 kgf∙cm-2) and a high content of total soluble solids (16.96 °Brix), compared to the control fruits (2.26 kgf∙cm-2 and 15.8 °Brix, respectively); this coating extended the postharvest period to 21 days. The edible coatings did not affect the cuticle color of ‘Ataulfo’ mango fruits and retained their typical yellow color