Bioethanol Production From Pineapple Wastes

<p>There is great interest in producing bioethanol from biomass and there is much emphasis on exploiting lignocellulose sources, from crop wastes through to energy-rich crops. Some waste streams, however, contain both cellulosic and non-cellulosic sugars. These include wastes from pineapple processing.</p> <p>Pineapple wastes are produced in large amounts throughout the world by canning industries. These wastes are rich in intracellular sugars and plant cell walls which are composed mainly of cellulose, pectic substances and hemicelluloses. The purpose of this study was to investigate the potential to transform such residues into ethanol after enzymatic saccharification of plant cell walls, and fermentation of the resulting simple sugars using the <em>Saccharomyces cerevisiae</em> NCYC 2826 strain. Three different fermentation modes, direct fermentation, separate hydrolysis and fermentation, and simultaneous saccharification and fermentation of the biomass were tested and compared. The results show that the main sugars obtained from pineapple waste were: glucose, uronic acid, xylose, galactose, arabinose and mannose. The highest ethanol yield was achieved after 30 hours of simultaneous saccharification and fermentation, and reached up to 3.9% (v/v), corresponding to the 96% of the theoretical yield.</p>

Anatomical, chemical, and biochemical characterization of cladodes from prickly pear [Opuntia ficus-indica (L.) Mill.]

Opuntia ficus-indica cladodes represent the green stem of the plant and are generally used as animal feed or disposed of in landfills. The present work investigated the anatomical and chemical composition of Opuntia cladodes, which form the basis of their pharmacological effects. Glucose and galacturonic acid were the main sugars of Opuntia cladodes, whereas high-performance liquid chromatography (HPLC) analysis showed the presence of mainly kaempherol and isorhamnetin glycosides (glucoside and rhamnoside). The presence of high amounts of calcium oxalate crystals was demonstrated by light microscopy on fresh and lyophilized cladodes. No antimicrobial activity was observed even after enzymatic treatment. O. ficus-indica cladodes may retain material tightly associated with cell-wall components, and this property will have the potential to greatly reduce the bioavailability of bioactive compounds.

Release of protein, lipid, and vitamin E from almond seeds during digestion

The evaluation of the bioaccessibility of almond nutrients is incomplete. However, it may have implications for the prevention and management of obesity and cardiovascular disease. This study quantified the release of lipid, protein, and vitamin E from almonds during digestion and determined the role played by cell walls in the bioaccessibility of intracellular nutrients. Natural almonds (NA), blanched almonds (BA), finely ground almonds (FG), and defatted finely ground almonds (DG) were digested in vitro under simulated gastric and gastric followed by duodenal conditions. FG were the most digestible with 39, 45, and 44% of lipid, vitamin E, and protein released after duodenal digestion, respectively. Consistent with longer residence time in the gut, preliminary in vivo studies showed higher percentages of nutrient release, and microscopic examination of digested almond tissue demonstrated cell wall swelling. Bioaccessibility is improved by increased residence time in the gut and is regulated by almond cell walls.

Enzymatic hydrolysis of flavonoids and pectic oligosaccharides from bergamot (Citrus bergamia Risso) peel

Pectinolytic and cellulolytic enzymes (Pectinase 62L, Pectinase 690L, and Cellulase CO13P) were used to evaluate the solubilization of carbohydrates and low molecular weight flavonoids from bergamot peel, a major byproduct of the essential oil industry. The enzymes were characterized for main-chain and side-chain polysaccharide hydrolyzing activities and also against pure samples of various flavonoids previously identified in bergamot peel to determine various glycosidase activities. The addition of Pectinase 62L or 690L alone, or the combination of Pectinase 62L and Cellulase CO13P, was capable of solubilizing between 70 and 80% of the bergamot peel, and up to 90% of the flavonoid glycosides present were cleaved to their aglycones. Cellulase CO13P alone solubilized 62% of the peel but had no deglycosylating effect on the flavonoid glycosides. Over a 24-h time course, a rapid release of cell wall carbohydrates was observed after treatment with Pectinase 62L, with a concurrent gradual hydrolysis of the flavonoid glycosides. Size-exclusion chromatography of the solubilized extract showed that after 24-h incubation, the majority of the solubilized carbohydrates were present as monosaccharides with a smaller proportion of oligosaccharides.

Characterization of flavonoids and pectins from bergamot (Citrus bergamia Risso) peel, a major byproduct of essential oil extraction

Bergamot peel is an underutilized byproduct of the essential oil and juice-processing industry. As with other Citrus peels, it still contains exploitable components, such as pectins and flavonoids. Commercial glycoside hydrolases, specifically a combination of pectolytic and cellulolytic enzymes, solubilized a high percentage of the material (81.94%). The flavonoid profile of the peel consisted of characteristic Citrus species flavanone rutinosides and neohesperosides derived from naringenin, eriodictyol, and hesperetin. In addition, a number of minor flavanone and flavone glycosides, not found in orange and lemon peels, were identified. The majority of flavonoids were extracted in the two 70% v/v EtOH extractions. Processing this material clearly has economic potential leading to low environmental impact.