Sources Of Starch Pdf Download
Pineapple plant (Ananas comosus) is one of the largest productions in Asia and its increasing production has generated a huge amount of pineapple wastes. Pineapple plant stem is made up of high concentration of starch which can potentially be converted into value-added products, including amino acids. Due to the increasing demand in animal feed grade amino acids, especially for methionine and lysine, the utilisation of cheap and renewable source is deemed to be an essential approach. This study aimed to produce amino acids from pineapple plant stem hydrolysates through microbial fermentation by Pediococcus acidilactici Kp10. Dextrozyme was used for hydrolysis of starch and Celluclast 1.5 L for saccharification of cellulosic materials in pineapple plant stem.
Sources Of Starch Pdf Download
The hydrolysates obtained were used in the fermentation to produce methionine and lysine. Pineapple plant stem showed high starch content of 77.78%. Lignocellulosic composition of pineapple plant stem consisted of 46.15% hemicellulose, 31.86% cellulose, and 18.60% lignin. Saccharification of alkaline-treated pineapple plant stem gave lower reducing sugars of 13.28 g/L as compared to untreated, where 18.56 g/L reducing sugars obtained. Therefore, the untreated pineapple plant stem was selected for further process. Starch hydrolysis produced 57.57 g/L reducing sugar (100% hydrolysis yield) and saccharification of cellulosic materials produced 24.67 g/L reducing sugars (56.93% hydrolysis yield). The starch-based and cellulosic-based of pineapple plant stem were subjected as carbon source in methionine and lysine production by P. acidilactici Kp10.
In conclusion, higher methionine and lysine production were produced from starch-based hydrolysis (40.25 mg/L and 0.97 g/L, respectively) as compared to cellulosic-based saccharification (37.31 mg/L and 0.84 g/L, respectively) of pineapple plant stem.
Starch is the most abundant molecule on earth after cellulose and the major carbohydrate reserve in plants. Starch is a major energy source on earth, providing up to 80% of the calories consumed by humans . Starch is a carbohydrate extracted from agricultural raw materials which is widely present in literally thousands of everyday food and non-food applications. Starch is a so-called green alternative material and is a most promising candidate for future use  due to its low cost, availability from renewable resources, and broad-ranged capability in food and non-food products. Basically, starch is a carbohydrate material that exists naturally as granules. Starch granules are normally found in seeds, roots, tubers, stems, and leaves. Demand for native starches increased globally, as it can minimise the use of chemically modified starches. Native starches have many applications in the food industry, pharmaceutical industry, paper making industry, cosmetics industry, etc. The starch industry separates the components of the plant: starch, protein, cellulose envelope, soluble fractions, and others, such as lignocellulosic material, as found in pineapple plant stem or basal stem (Fig. 1). However, the methods of manufacture are specific to each plant and the industrial tools are normally dedicated to a raw material. Starch is usually used in its native form, where it was extracted from raw materials in its purest form. However, modifications on the native starch, termed modified starch, can be carried out to obtain certain properties or better characteristics of the starch, either through physical, chemical, enzymatic or genetic modifications .
The utilisation of pineapple plant stem as alternative starch supply made it possible for the conversion of waste into wealth. This study aimed to produce amino acids from pineapple plant stem hydrolysates through microbial fermentation by Pediococcus acidilactici Kp10. Dextrozyme was used for hydrolysis of starch and Celluclast 1.5L for saccharification of cellulosic materials in pineapple plant stem.
All the chemical compositional analyses were done using standard method. All analyses were done in triplicates. The starch content was determined based on the method by Nakamura et al.  with slight modification of absorbance at 580 nm. While, the method used in the determination of lignin, hemicellulose and cellulose content of the sample was modified based on the method reported by Iwamoto et al. . The hydrolysates obtained from the hydrolysis and saccharification process were subjected to simple sugars determination using High-Performance Liquid Chromatography (HPLC) based on method explained by Linggang et al. . A Rezex RPM-Monosaccharide Pb+2 column and RI detector were used. The mobile phase was deionised water at a flow rate of 0.6 mL/min. The analysis was performed at 80 C. Standard solutions were prepared by dissolving appropriate masses of glucose and xylose in deionised water. The retention times of glucose and xylose were 15.42 min and 16.96 min, respectively.
In this study, the nitrogen content of the pineapple plant stem was recorded at 1.85%. This result was in agreement with the nitrogen content of pineapple plant stem reported by Hanafi et al. , where the pineapple plant stem of Moris and Gandul pineapple plant was reported at 1.55% and 1.63%, respectively. Since the underground part of pineapple plant stem was used in this study, the nitrogen content obtained might be affected by the nitrogen content in soil and the plant cultivars. Crude protein consists of true protein and non-protein nitrogen, where nitrogen accounts for 16% of all biological proteins on average. In this study, pineapple plant stem contained as much as 11.56% crude protein, which was even higher than the result obtained by Zainuddin et al. , where Moris pineapple leaves have a crude protein of 7.05%. The amount of crude protein can vary according to the stage of plant growth as well as the parts of the plant . The protein content and composition can also be affected by environmental conditions and nutrients availability in soils, especially nitrogen fertilisation and the strategy of its application . Crude fat content in pineapple plant stem measures the estimation of total fat content, including triacylglycerides, alcohols, waxes, terpenes, steroids, pigments, esters, aldehydes, and other lipids . The crude fat content in the pineapple plant stem used in this study was recorded at 1.53% on a dry weight basis. As the primary components of biomass, carbohydrates are the most potential biomass component in a biorefinery process, since it acts as storage polysaccharides (starch) or structural polysaccharides (cellulose, hemicelluloses, pectin, and chitin) . Pineapple plant stem used in this study has reported a carbohydrate value of 9.91% on a dry weight basis, which indicated that it consisted of quite a number of sugars and starch; thus, it is a potential biomass to be used in the production of value-added products, such as amino acids.
Pineapple plant stem consisted of high starch and cellulosic content, which made it great potential biomass. The starch content was 77.78% on a dry weight basis. Nakthong et al.  reported a starch content of 97.77%, with amylose content 34.37% (w/w) of the whole sample. The percentage of starch content in this study was the highest in pineapple plant stem as compared to other chemical compositions. This result was in line with the statement reported by Sanewski et al. , which stated that the stele of pineapple plant stem mainly consists of compact parenchyma with an abundant of the starch present. Thus, pineapple plant stem was expected to be potential starch-based biomass for amino acids production due to the high level of starch present, which can then be converted into fermentable sugars, mainly glucose, through enzymatic hydrolysis.
Gelatinisation was done before starch determination to break down the intermolecular association between amylose and amylopectin at solid state with heating . During heating in water, the starch present in the pineapple plant stem undergoes a transition process, where the starch granules swell and eventually break down into a mixture of polymers-in-solution, making the starch suspension viscous . This process changes the semi-crystalline phase of amylose and amylopectin to an amorphous phase . Thus, the ratio of amylose and amylopectin present in the starch can affect the gelatinisation temperature and properties . The value of lignin, hemicellulose and cellulose of pineapple plant stem were recorded at 18.60%, 46.15%, and 31.86%, respectively. Sodium chlorite treatment was used in the removal of lignin to determine the holocellulose content of the biomass. The holocellulose was then allowed to undergo alkali treatment using potassium hydroxide to further remove the hemicellulose content in the pineapple plant stem . The cellulose content of the pineapple plant stem was determined as the residue after complete removal of lignin and hemicellulose. The lignin content obtained in this study was comparable with the results obtained in pineapple leaves and pineapple plant stems as reported by Zainuddin et al. . The aforementioned author also claimed that plant maturation and parts of the plant used will affect the lignin content of the sample, in which the rigidity of the pineapple plant stem also contributes to the high lignin content.
Gelatinisation of pineapple plant stem involves a heating process in which the starch molecules are dissolved and the viscosity increases. At high temperature, the α-glucan chains of starch in pineapple plant stem become more susceptible to hydrolysis by amylase action due to the loss of its ordered structure . Dextrozyme was chosen as the enzyme used in starch hydrolysis, because it was found to be effective in breaking down the starch granules into fine particles. It consists of glucoamylase obtained from Aspergillus niger and pullulanase from Bacillus acidopullulyticus. Dextrozyme was the most effective in hydrolysing corn starch when being compared with other hydrolytic enzymes, namely, bacterial α-amylase, β-amylase and glucoamylase as reported by Ma et al. . The concentration of glucose in pineapple plant stem hydrolysate was 62.91 g/L. The high amount of glucose produced indicated that starch content in pineapple plant stem is a potential carbon source to be used in fermentation for amino acids production.