Although abaca fibers are obtained from the petioles of abaca leaves, its harvesting is not simple. It requires a set of highly laborious activities involving several opera­tions that range from separation of primary sheaths from secondary ones to extrac­tion and to pre-processing of the fiber (to obtain raw fiber) for various industrial applications. The main operations involved in its extraction include:

1. Tuxying

2. Stripping

3. Drying

The tuxying operation involves the separation of primary sheaths from secondary ones. In this process, the petiole’s outer layer (fiber-bearing layer) is removed in the form of strips or tuxies, which are then freed at one end and pulled off. The stripping operation or cleaning operation involves the scraping of the pulpy material from outer fibrous layer of the petiole for extracting the fiber strands. The stripping is done either by hand or by use of machines. In the Philippines, generally hand-stripping is

practiced while in Central America (Costa Rica), machine-decortication is being done in which the stalks are cut into 0.6-2 m long strips followed by their crushing and scraping inside the machines to yield fibers. In the drying operation, the extracted raw fibers are dried by hanging them in the sun (sun-drying) or by advanced mechan­ical drying as employed in Central America. After drying of the raw fiber, it is then graded on the basis of fiber quality. The excellent or high-quality fibers are separated from the rest and are combed to detangle and removal of other impurities. Moreover, the further processing of the extracted fibers depends on their quality-related param­eters and hence different grades are utilized for different set of industrial activities.

The quality of abaca fiber is determined by many parameters like extraction pro­cedure, strength, fiber length, color, and texture. Based on the cleaning or stripping process the abaca fiber has been classified into various grades as given in Table 3.2. In addition to these mentioned grades, the dried thin strips (5 mm or 1/8th inch wide) of abaca leaf sheaths is called “Lupis” and the outermost light brown covering of the abaca stalk (petiole) is called “Bacbac.” The different grades of abaca fibers are then put into various industrial or other uses as listed in the Table 3.3.

About 200 varieties of abaca are known to exist in Philippines of which only a few varieties are cultivated on a large scale, e. g., Bongolanon, tangongon, and Maguindanao. However, the new and better varieties are being introduced and recommended for abaca cultivation, which includes Inosa, Laylay, and Minenonga

(Lomerio and Oloteo 2000; FIDA 2009). It has been reported that the immature (8-10 month old) stalks of abaca variety “Inosa” provide an excellent material for paper and pulp industry due to their desirable properties like low lignin/ash and high a-cellulose/holocellulose/hemicelluloses content (Moreno and Protacio 2012). Moreover, the hybrid varieties particularly Canarahon x Korokotohan (1841-series) has been found to be quite promising in terms of yield and fiber quality (Moreno 2001). The important characteristics of abaca varieties (“Inosa,” “Laylay” and “Minenonga”) recommended for cultivation in Philippines are listed in Table 3.4.

In addition to the above mentioned varieties, NARC (National Abaca Research Centre, Philippines) have identified and selected five new accessions for fibercraft industry and about seven accessions for paper and pulp industry. Some of which include NARC-MIO, NARC-M107, NARC-159, NARC-M168, and NARC-M179. These accessions have been selected as promising ones due to their high fiber- yielding ability, long fiber length, appropriate texture, uniform fiber strand, and higher tensile strength. Moreover, the accessions selected for pulp and paper indus­try were found to have higher flexibility, strong folding strength, and higher resis­tance to mechanical damage like tearing (qualities required for production of high-quality paper, i. e., thin, strong, and highly porous paper). As far as the chemi­cal composition of the selected accessions is concerned, they have been found to contain higher cellulosic content (holocellulose (83.02-86.90 %), a-cellulose (52.50-64.21 %), and hemicellulose (16.23-26.20 %)) and lower ash content (0.84-1.72 %) (Moreno et al. 2005).