*5.1.2 Crop factor-based estimation*

It is the best available method to estimate crop water requirement from direct measurements of crop evaporation. Water requirements of crops are closely related to evaporation (evaporation of water from the soil surface) and transpiration (evaporation of water through leaves) when combined called evapotranspiration. Evaporation can be easily measured but transpiration is not. Therefore, it is much simpler to relate crop evapotranspiration to daily evaporation *via* crop factor. In this method, penman's estimate of evaporation is multiplied by the appropriate crop factor to estimate the potential evapotranspiration.

A crop factor can be defined as the percent of ground covered by the crop canopy, which varies according to the crop and stage of the crop. For palm oil, the internationally approved crop factor for an adult palm is 0.7.

The following simple method of calculation has been devised based on the evaporation rates prevailing in the area, especially during the summer months. For example, the highest average of pan evaporation during peak summer months is taken as 6.70 mm. The requirement of water per palm per day is estimated as follows:

Evaporation from open pan: 6.70 mm.

Crop factor: 0.7.

Potential evapotranspiration PE Pan evapora ( ) = tion Crop factor ×

PE 6.07 0.7 4.69 mm / day = ×=

As 1 mm of rainfall is equal to 1 L/m2 = 46,900 l/day/ha.

Since 143 palm trees are planted on one hectare of land, the amount of water per palm tree per day is up to 328 liters.

Water storage capacity of not less than 70% of field capacity is acceptable and will not significantly affect the FFB yield of palm oil.

Therefore, the amount of water to be applied will be:

4.69 mm 70% 3.283 mm / day or 32.830 lit. / ha / day o × = r 230 lit. / palm / day

#### **5.2 Processing of palm oil**

The first fruit bunches ripen 3–4 years after planting. Normally palm oil takes about 180 days from the time of emergence of the inflorescence to the maturation of palm oil fruit bunch. The majority of the oil formation in the fruits takes place during the last 2–3 weeks of fruit ripening. Harvesting of over-ripe fruits results in poorquality oil with high FFA content. Palm oil fruits contain an enzyme called lipase, which splits the oil into undesirable free fatty acids leading to quality problems during storage, processing, and refining. Care must be taken to cause minimum damage to the fruit bunches and transportation of harvested fruit bunches to the processing unit with a minimum delay to reduce the activity of enzyme lipase.

#### **5.3 Oil biosynthesis**

Young fruits during the first two weeks of development contain very little lipids (5–10% per fresh weight). Storage of oil synthesis in palm oil mesocarp can be detected as early as 12 weeks after anthesis. A high rate of oil accumulation begins at 16 weeks and stops when the fruits ripen about 20 weeks after anthesis. Oil is stored in oil bodies found in the cytoplasm of mesocarp cells of ripe fruits. Small oil bodies may already be observed at about 13 weeks after flowering when oil synthesis begins. Oil accumulation in kernel begins about 12 weeks after flowering and stops at 14 weeks. During this time, the kernel gradually hardens [2]. The fatty acids in the mesocarp of young fruits consist mainly of polyunsaturated linolenic acid (18: 3) and linoleic acid (18: 2). When rapid oil accumulation begins the level of linolenic drops to an insignificant value, while the level of linoleic also drops but is stably maintained at 10% in ripe fruits.

Quartering is the process in which the fruit bunches are cut into smaller portions followed by stripping or loosening of the fruits from the bunch and spikelets.

#### *Management and Processing of Palm Oil (*Elaeis guineensis *Jacq): The Crop for Future DOI: http://dx.doi.org/10.5772/intechopen.108579*

Processing of palm oil fruits for edible oil has been practiced in many countries. Crude palm oil (CPO) is obtained from the fruit of the palm oil tree (*Elaeis guineensis*), which is a rich source of palmitic acid, β-carotene and vitamin E. Extraction of palm oil from fresh fruit bunches (FFB) involves field and factory operations. The techniques for processing palm oil fruit vary with available technology, and this will greatly influence the type and quality of the oil produced. The extraction of oils from freshly harvested fruit bunches involves five major operations: sterilization, fruit loosening, digestion, oil extraction, and clarification.

#### **5.4 Sterilization of fruits**

Sterilization or cooking is the process to use high-temperature wet heat treatment to loosen the fruits from the bunch. Stripping prevents free fatty acids build up in the oil and softens the fruits in the bunch to facilitate easy striping. The heat that is produced during sterilization destroys the lipase enzyme and arrests hydrolysis and autoxidation. Heat produced during sterilization will coagulate the nitrogenous and mucilaginous matters to prevent the formation 0f emulsions in the crude palm oil during the process of purification. It also helps in breaking up the oil-carrying cells of the mesocarp to release the oil during the digestion process.
