1. INTRODUCTION:

In a world starch market dominated by corn, potato, and tapioca, the world production of starch has been estimated to be 27.5 million mt, with an insignificant amount of sago starch consumed, about 3%, 200,000–300,000 mt per annum. Clearly, there is a need to enhance the importance of sago as a major crop in Southeast Asia for global recognition¹.

Sago is made from Tapioca is flavorless, colorless, odorless starch extracted from the roots of the plant species Manihot esculenta. Sago will be in the form of pearls similar in appearance. Sabudana (Tapioca Pearl/Pearl Sago) is a vegetarian processed food. Commonly known as Sago in India, Sabudana is made from the starch extracted from Tapioca root (tuber). Commercial product of Sabudana is in the shape of small pearls. Sago starch has been used for a long time, especially in Southeast Asia in the food industry for the production of sago pearl, vermicelli, bread, cake, biscuits, and many other traditional foods². Sabudana is high carbohydrate low fat food used across states in India. In India, sabudana is the first food item (apart from milk) most Indians feed to new-born and is also consumed by most to break their fast during festivals. Sabudana is preferred over other food items because it is full of starch and does not contain any artificial sweeteners or chemicals. Sabudana/Sago are also used as a health food for sick as it gives quick energy and is easy to digest. It is a well-known fact that sabudana has cooling effect on our system and hence sabudana-gruel is given to people who have excess bile³.

Basically, Sago can be classified into two varieties such as roasted and boiled. The roasted sago is white in color, and the boiled sago is transparent and will have a glassy look. The major application for Sago is sweet pudding made by boiling sago with either water or milk and adding sugar and sometimes additional flavourings. Chemical or residue free pregelatinized sago balls has lot many advantages from consumer health point of view.

The Salem starch and sago manufacturers service industrial co-operative society ltd, Tamilnadu, India reports that in India tapioca is grown over an area of about 3 lakhs hectares, with a production of 58 to 60 lakhs tones of tubers. Though Kerala ranks first in cultivation and production in the country. Tamilnadu stands first in respect of processing of tapioca into starch and sago and hence this crop has now acquired a status of one of the important commercial crops in the State. Tapioca Root is the basic raw material for Sago and starch. Raw tuber contains 30 to 35% starch content. Native Tapioca Starch is a food grade product refined from cassava roots. It is used for its bland flavor profile. It is a white to off-white powder with a moisture below 13%. Gelatinization temperature: 59 – 65°C. The pH of a slurry in water is neutral. Normal native starches consist of a mixture of 15-30 per cent. amylose and 70-85 per cent. amylopectin. Amylose structurally is a linear polymer of anhydroglucose units, of molecular weight approximately between 40 000 and 340 000, the chains containing 250 to 2000 anhydroglucose units. Amylopectin is considered to be composed of anhydroglucose chains with many branch points; the molecular weight may reach as high as 80 000 000 (Re. WHO). Amylose is an unbranched chain which is coiled in the shape of a helix. Amylose contributes to the gelling property of starch whereas amylopectin contributes high viscosity⁴.

Several Oxidizing and cross linking chemicals are used on the Sago processing are know from prior art. The preference for the use of "natural" (not chemically modified) ingredients in food preparations, a starch preparation that is unmodified by reaction with chemical modifiers or derivatization would offer several advantages for use in gelled food systems without chemical residue in the consumer's diet⁵.

It is known from prior art that the tapioca tuber or root, received from the farms is hygienically cleaned in water and after peeling the skin, it is crushed, allowed passing the milk after retaining all fiber and impurities⁶. The milk is settled in a tank for nearly 3 to 8 hours, thus all residual impurities float to the top of the tank and are drained out of the settled milk. From this settled Milk Cake several oxidizing and cross linking chemicals are added to reduce the viscosities and the Globules made, roasted and dried.

Enzyme based process would be most appropriate process to obtain chemical free Sago for gelling. Accordingly, there is a need for a pre-gelatinized or instant gelling starch that forms soft gels and that should be free from chemical residues. Raw starch hydrolyzing aminoglucosidase and Protease hydrolysis to disintegrate the protein configuration with amylase and amylopectin and amylopectinase to reduce the viscosity to suit the gel. Further, there is a need for a sago gel that has a smooth texture and lack of chemical odor or graininess often found in cold water dispersible starches and the present invention is on enzymatic process to reduce the viscosity and optimal discharge of the reducing sugar to increase the softness of the Sago balls after roasting⁷.

Modern methods of Sago process:

TUBER SELECTION

RASPING

DESANDING

FRUIT WATER REMOVAL

FIBER EXTRACTION

FIBER SEPRATION

CHEMICAL METHODS	NATURAL FERMENTATION

VISCOSITY REDUCTION	VISCOSITY REDUCTION (12 to 24hrs)

SIZING	SIZING

DRYING	DRYING

ROASTING	ROASTING

PACKING	PACKING

Microbial fermentation based viscosity reduction is time consuming, hence there is a need for an online process with quick control over viscosity reduction that can be achieved by selective appropriate enzymes and conditions to processes the sago to achieve residue and chemical free sago.

This study describes about the methods of using enzymes to reduce number of days or time involved to reduce the viscosity of the starch and without compromising the gelling properties and further the process limits the usage of the chemical agents and enables to make naturally processed sago balls. The application of enzymes for the conversion of the Tapioca starch in to processed soft and transparent sago balls used in food preparations.

2. SAMPLE COLLECTION:

Native sago starch extracted from the pith of the sago palm tree collected from local market.

3. MODERN METHOD FOR EXTRACTION OF SAGO STARCH:

The domestic level is practiced by the individual farmers where sago palms are felled and processed in the garden, thus without the need to transport the heavy trunk. After felling the trunk with an axe, it is split lengthwise segments. These segments are fed into slicers that slice the pith from the bark⁸. In certain other factories, the bark was first removed from sections of the logs. Each of the debarked sections of about 80 – 100 cm long, is fed into the mechanical rasper (with chrome nails mounted on one face of a disc or a drum). This rasped the pith into finer pieces which are fed into the hammer mill via conveyor belt⁹. The resulting starch slurry is made to pass through a series of centrifugal sieves to separate the coarse fibres. Separator outlet free from maximum fiber before fermentation stage. Super cake is formed from the outlet after 10 to 12 hrs open fermentation. Nylon inlet carry over from immediate super cake outlet for filtration. Sago liquid (Nylon) and Sago cake (Nylon) sediments are formed after filtration process. Sago cake (Nylon) fermentated for a week to month. Further purification is achieved by separation in a nozzle separator through sieve bends. A series of cyclone separators have also been used to obtain pure sago starch¹⁰.

4. ENZYME HYDROLYSIS:

Enzymatic process to reduce the viscosity and optimal discharge of the reducing sugar for soft to produce the chemical free residue pre-gelatinized sago starch balls. Enzyme based process would be most appropriate process to obtain chemical free sago for gelling. Accordingly, there is a need for a pre-gelatinized or instant gelling starch that forms soft gels and that should be free from chemical residues. 1000 Kg of the fiber free tapioca sago starch 45 % slurry is treated with 0.01 % raw starch hydrolyzing Aminoglucosidase and Protease hydrolysis to disintegrate the protein configuration with amylase and amylopectin at the initial pH is 7.4. To reduce the viscosity to suit the gel 0.01 % amylopectinase enzyme is added and reacted for 10 to 15 minutes and pH reduced to 4.5.

4.1 Viscosity Analysis:

Different types of samples from the sago starch extraction process and product obtained from enzyme hydrolysis taken for viscosity analysis. The most appropriate viscosity determination is performed with Brookfield Viscometer Model DV II + by using Spindle RV4 and temperature at 50°C at 100 RPM.

The data confirm the reduction of the viscosity from Separator Outlet 1510 cps to Super Cake1380 cps to Nylon Inlet Liquid 1220 cps to Nylon Cake 1095 cps. The viscosity of sago after enzyme hydrolysis was 750 cps was shown in the Table 1. The viscosity analysis Accuracy: +/- 1.0% of range Repeatability: +/- 0.2%.

Table 1: Viscosity analysis

S. No	Sample ID	Viscosity (cps)
1	Separator Outlet	1510
2	Super Cake	1380
3	Nylon Inlet Liquid	1154
4	Nylon Cake	1254
5	Sago starch	1095
6	Sago starch after enzyme hydrolysis	750

4.2 Reducing sugar analysis:

Different types of samples from the different process of extraction taken for reducing sugar analysis. Reducing sugar test were analysed by Atomic Absorption Spectrometry for Dried samples. A Perk and Elmer 380 atomic absorption spectrometer furnished with a copper hollow-cathode lamp was used. The instrument was set at 324.7 nm and the air-acetylene flame was adjusted according to standard recommendations¹¹. Dewatering of starch is carried out using a hot air oven for drying at 100°C to obtain sago powder.

It is evident for the study that the RS of the raw starch before fermentation is 0.488 mg/g or g/Kg and after fermentation is 3.737 mg/g or g/Kg this is the modification or loss to reduce the corresponding viscosity, after fermentation the RS is discharged in to the supernatant. The calculation needs to be X mg/g RS * the Qty of the water Y will result the net removal of sugar to achieve the pH as mentioned above. Sting coupled drying concentrates from 40 % moisture to 4 to 6 % means the presence of the RS Sago balls which is concentrated by loss on drying and that the reason we get higher values for the respective final products.

Table 2: Reducing Sugar Analysis by AAS

S. No	SAMPLE	RS (mg/g)	RS (%)
1	Separator Outlet	6.042	0.604
2	Super Cake	7.450	0.745
3	Nylon Inlet Liquid	7.432	0.743
4	Nylon Cake	6.060	0.606
6	Sago starch	6.131	0.613
7	Sago starch after enzyme hydrolysis	9.232	0.923

4.3 Retrogradation:

Retrogradation of starch in which the reassociation of the amylopectin or amylose molecule after the gelatinization can be observed during the cooling process. Storage at higher temperature reduces retro-gradation. The retro-gradation is arrested with the elevated temperature in processing the enzyme treated sago under steam under pressure at 70°C at 0.6 bar pressures for 60 minutes.

4.4 Sago starch balls:

Moist sago starch is used to make a popular native food, pearl sago. In its preparation, the moist starch cake is pressed through a perforated sheet of iron or coarse screen¹². The pellets of starch are put into a shallow hammock-like contrivance to which a circular swinging motion is imparted. Swinging this contraption in the correct manner imparts a rotary motion to the pellets which, provided the moisture content is correct, assume a roughly spherical shape. The process is rather a kin to pin-rolling. The pearls are sieved for removal of ﬁne particles and large aggregates and roasted in shallow metal pans, which partly gelatinize and dry the sago pellets. These are then graded into large and small ‘bullet’ or ‘pearl’ sago. The pearls are subsequently dried, sorted and sold¹³. Reduced viscosity of sago starch balls by enzymatic process which improves softness and gelling property.

4.5 Applications of sago starch balls:

Application of enzymes for the conversion of the Tapioca starch in to processed soft and transparent sago balls used in food preparations. These pearls are often used to prepare the ‘three palm pud-ding’: sago pearls, cooked in coconut milk, and topped with sugar from the sugar palm (Arenga pinnata). Other application of Sago starch balls was shown in the Figure 1.

Figure 1: Application of sago starch balls

5. CONCLUSION:

Chemical and residue free pre-gelatinized sago starch balls was produced through enzymatic process. This sago starch ball improves softness and gelling property raw starch hydrolyzing Aminoglucosidase are thermally inactivated by roasting and drying. Amylopectinase hydrolyzing enzyme for viscosity reduction. From the analysis, it was to conclude that Neutral protease and amylopectinase enzymes used for viscosity reduction process from 1500 to 750 cps and reducing sugar discharge from 5 to 10 mg/g for soft to produce the chemical free residue pregelatinized sago starch balls. The retro-gradation is arrested with the elevated temperature in processing the enzyme treated sago under steam under pressure at 70°C at 0.6 bar pressures for 60 minutes. The application of pre-gelatinized sago starch balls can be used in various food preparations.

6. REFERENCE:

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Received on 08.12.2022 Modified on 05.01.2023

Research J. Science and Tech. 2023; 15(1):15-19.

DOI: 10.52711/2349-2988.2023.00003