New Potato Varieties ( Solanum Tuberosum L.) as Raw Material for Chips and Frech Fries

. The purpose of this study was to determine the quality of raw material of potato for chips and french fries from various prospective varieties and shelf life in the room temperature. The research was conducted with an experimental method using a non-factorial in randomized block design with one treatment factors, each of which was repeated 3 times. The treatment was the potato variety consisting of seven new high-yielding variety candidates namely : a1 = clone 41, a2 = clone 16, a3 = clone 17, a4 = clone 09, a5 = Atlantik, a6 = Medians, a7 = AR-08 variety. These potato clones had different characteristics in specific gravity, dry matter, reducing sugar, moisture, starch, content, color, taste, crispyness and appearance of the resulting french fries. The best clones for potato chips and french fries were clone 16, atlantic, medians and AR-08. These clones can be used as raw material for the potato chips and french fries industry.


Introduction
Potato (Solanum tuberosum L.) is one of the most widely grown vegetables in Indonesia.Potatoes can be used for various household and industrial purposes.Potatoes are considered as a non-fattening, nutritious and wholesome food, containing carbohydrates (16%), proteins (2%), minerals (1%), dietary fibres (0.6%) and is a good source of vitamin C and antioxidants [1] In countries with cold climates, potatoes are consumed as a staple food, while in Indonesia they are consumed as vegetables and snacks.In the food industry, potatoes were processed into potato chips [2], frozen french fries [3], dehydrated mashed potatoes-potato granules [4] dehydrated mashed potatoes-potatoes flakes [5], dehydrated diced potatoes [6] potato starch [7], potato flour [8] canned white potatoes [9] french fries, potato croquettes, potato pastels, potato donuts, potato cakes, potato fried chili sauce, and potato fried chili sauce.
Potatoes as industrial raw materials are mostly used as chips and french fries.One of the impacts of the increasing number of fast food restaurants in urban areas is the increasing demand for potato chips and french fries.The productivity of Indonesian potatoes was quite high, reaching 1.36 million tons/year which was potato as a vegetable ingredient.All french fries on the market was still imported with an import volume of 52,280 tons/year (BPS, 2022).In countries that consume potatoes as an alternative to carbohydrates, they have a high level of consumption per capita for example in 2020 India 25 kg per capita, China 47,24 kg per capita, whereas Indonesia 4,3 kg per capita (FAOSTAT, 2023).
The varieties used for processed industries were the Atlantic imported from Canada, Australia and Scotland.Atlantic varieties were suitable to be used as raw material for potato chips, because of the tasty taste, with the characteristics of specific gravity (SG) high at 1.078 to 1,087 [10] thus providing high yield of chips.But according to farmers planting the varieties were less liked because the lower yield of granola, it cannot resist the leaf (Phytophthora infestans), not withered bacteria (Ralstonia solanacearum) and the degeneration period is very quick [11].
The role of postharvest technology in the potato processing industry, in addition to the right processing aspects, also prepares the expression of the exact quality of the raw material, exactly number, and on time.For this reason, an integrated effort has been needed since the selection of varieties, cultivation technology, harvest and fresh handling.Previous test results (2016 to 2017) obtained by the results of a new superior variety (VUB) processed potato for raw material chips and several clones of hope for raw materials of industrial potatoes.The source of raw potato tubers has a significant effect on color and texture of french fries.Controlling these variations is crucial to ensuring a consistent, high-quallty end product [12] Potato tubers were harvested in large quantities and require time to be sorted before being sent to the food processing industry, as a result, these tubers cannot be directly converted into processed products in one production.So to find out and obtain good quality french fries products, it was necessary to do research on potato storage as raw material for making french fries.The purpose of this study was to determine the quality of raw material of potato tuber for chips and french fries from various prospective varieties and shelf life in the warehouse.From this research, it was hoped that it can produce information about the quality performance of chips and french fries from various prospective varieties and the length of storage in the warehouse.

Materials and metodology
The research was conducted using an experimental approach in the laboratory.In this approach, various treatments were designed which were thought to have an effect on improving product quality.To determine the effect, observations were made on important parameters which were then analyzed and interpreted.The materials used include 7 prospective potato varieties for chips and french fries.Chemicals for the analysis of starch and reducing sugars, supports, and other equipment.

Results and discussion
Moisture content, starch, reducing sugar content, Total Soluble Solid (TSS), and tuber specific gravity can be seen in Table 1.

Moisture content
In Table 1, the moisture content ranged from 79.40 to 83.30%.The AR-08 variety had the lowest moisture content (79.40%) and the highest moisture content clone 41 (83.30%).In contrast to the results of research Asgar [14] which states that the moisture content of various clones was different.The difference in moisture content was caused by differences in dry matter.Good tubers used as raw materials must have a low moisture content so that they did not crumble when fried, this was related to the dry matter content.High dry matter content was a must to obtain good tuber processing results.A good dry matter content for processed potatoes was at least 16.7% with a moisture content of 83.3% because it will give a crunchy taste.The moisture content of each clone was not significantly different.So, clone 41, clone 16, clone 17, clone 09, Atlantic, Medians, and AR-08 could be accepted as raw materials for potato chips and french fries.The decrease in moisture content was a complex phenomenon that can occur due to morphological, physiological, and environmental factors.During the storage period, potato tubers will continue to experience respiration and transpiration, utilizing water and sugar reserves so that the product continues to experience a decrease in turgidity and weight which causes the product to shrivel and shrink [15]

Starch content
In Table 1, the starch content ranged from 11.83 to 15.35%.The highest starch content was found in clone AR-08 (15.35%) and significantly different from the starch content of clone 41 (11.92%), clone 09 (11.83%).Differences in starch content were caused by genetic differences.This is in accordance with the opinion [16] that starch contents was significantly influenced by variety.In addition to genetic factors, the starch content in potato tubers was also influenced by the level of tuber maturity, environmental conditions during growth and the characteristics of potato cultivars.
According to Zhang Wen-kui [17], the use of N fertilizer (80 kg/ha) and farm manure (farmyard manure) was 10 tons/ha, with the addition of nitrogen fertilizer up to 120 kg/ha and the addition of a certain amount of phosphate and potassium, the production and content of potato starch can be increased.The use of fertilizer doses can increase the ability of assimilation.In addition, the doses of phosphate and potassium fertilizers have different effects.To increase production and profits and improve quality, the dose of N 120 kg/ha, P2O5 80 kg/ha, K2O 180 kg/ha, farmyard manure 10 tons/ha.Increased availability of phosphorus in soil allowed the production of tubers with higher dry matter content, lower total sugar content, and a higher percentage of starch and protein [18].Potatoes with a high specific gravity, starch content was also high.Variety affected product composition and quality [19][16] Different varieties have different dry matter content [20] In addition to varieties, harvest age affects production and specific gravity.Harvesting at the age of 14 to 16 weeks after planting on Atlantic and Norchip varieties resulted in greater production and specific gravity [21] The higher the age of harvest, the higher the starch content [22] Starch content was influenced by location and growing season [23]

Reduction sugar
From Table 1, the reducing sugar content ranged from : 0.08 to 0.12%.There was no sigficantly different between clones on reducing sugar.Other researchers opinion, the reducing sugar content of potato tubers was influenced by clones and harvest age, among others.The right harvest age as raw material for french fries was 100 days.Harvest age was very influential on reducing sugar content [24][25] [26] stated that 2.5 to 3 mg/g (0.25% to 0.30%) of the wet weight (sampling) should be considered as the limit of permitted reducing sugar as raw material for the chip processing industry and french fries.So all potato clones as listed in Table 1 can be used as raw materials for potato chips and french fries because the reducing sugar content is lower than 0.25%.
According to Mareček [27], there are several factors that affect the total sugar content in potato tubers, namely variety, maturity at harvest, the effect of the year of planting.According to [28] the increase in reducing sugar causes an increase in the color of the french fries.Both amino acids and reducing sugars participate in the formation of potato color during frying, with the amount of reducing sugar being the limiting factor.Fructose produced the highest browning followed by glucose.The addition of sucrose practically did not change the final color of the french fries.Processing quality of potatoes for french fries is partially determined by reducing sugar content of the tuber [29].

Total soluble solid (TSS)
In Table 1, the Total Soluble Solid (TSS) ranged from: 3.40 to 4.13ºbrix.This shows different genetic factors as stated by Pardo [30], soluble solids content determination showed minimal difference between varieties.From Table 1 it can also be seen that TSS of clone 41 and the Medians were the smallest but not significantly different with clone 16, clone 17, clone 09, and AR-08.TSS of Atlantic was the highest among others but not significantly different with clone 16, clone 09, and AR-08.Total Soluble Solid (TSS) was all solid materials present and soluble in water in the tuber, including reducing sugars, sucrose, organic acids and water-soluble vitamins.
According to [31] TSS will affect the texture.The larger the value indicated on the Brix scale, the greater the amount of material or solid that was soluble in water.This shows that the quality of these commodities was getting lower.The content of soluble solids also has something to do with texture, where insoluble pectin was known as protopectin which was then enzymatically converted into soluble pectin during the storage process [32] so that TSS increased.[33] added that there was a breakdown of carbohydrates/starch into sugar so that the TSS content increased [33].

Specific gravity
From Table 1 the specific gravity ranged between : 1.05 to 1.13 and was not significantly different between clone treatments.According to Pantastico [31] and Abebe [34], the specific gravity has a correlation with the solid material content, the higher the solid material content, the higher the specific gravity and the clone was good as raw material.Furthermore, it was stated that the specific gravity of potato tubers can affect the oil content produced.The higher the specific gravity of potato tubers, the lower the oil content in the resulting chips [35].Thus, the specific gravity of potato tubers determines the quality of the preparation.According to information from Indofood, the minimum specific gravity for the chip processing industry standard was 1.07.So clones 09, Atlantic, Medians and clones AR-08 complied with Indofood standards.

Weight loss
Weight loss during storage 2 weeks to 12 weeks can be seen in Table 2.  2 it can be seen that the weight loss of each clone was different at the 2 nd , 4 th , 6 th , 8 th , 10th and 12 th weeks.The weight loss of each clone at each storage increased.This was caused by evaporation (transpiration) and respiration.This was in accordance with the experimental results of Asgar & Asandhi [36] that the longer the tubers were stored, the greater the weight loss.This was because the starch in potatoes is converted into sugar, CO2 and energy, causing a reduction in the weight of potato tubers stored at that temperature.Besides, tuber weight will decrease during storage.Potato tubers are 80% water.Loss of weight can be caused by water loss.The water in the tubers was easily lost at room temperature through the evaporation process.Evaporation of potato tubers will be greater at room temperature than at cold temperatures [37]

Rotten
The rot of tubers during storage 2 weeks to 12 weeks can be seen in Table 3.At week 6, there were several clones that experienced rot.During storage there is an increase in rotten tubers.Damage to tubers during storage is influenced by several factors, namely piles of tubers during storage, storage temperature and air circulation.Bulbs stored with a higher pile cause poor air circulation so that the warehouse becomes more humid.Humid air will support the development of pests and diseases.Theoretically, warehouses with room temperature (18 0 to 25 0 C) provide good conditions for the development of warehouse pests and diseases.The percentage of tubers that are attacked by pests and diseases can be seen in Table 3.In the 12 th week of storage, the number of tubers that were damaged by pests and diseases increased.Based on observations, tuber damage was mainly caused by potato tuber borer (Phthorimaea operculella Zell.), dry rot disease (Fusarium spp.), soft rot disease (Erwinia carotovora) and eye rot disease (Ralstonia solanacearum).Phthorimaea operculella Zell attacks from the field.The eggs attached to the bulbs will hatch and will eat the bulbs.The potato tuber borer is more common in the dry season.The development of Erwinia carotovara bacteria will be faster if the room conditions are warmer.The test results showed that seeds incubated at temperatures between 25 0 to 30 0 C were able to accelerate the development of Erwinia spp bacterial infection [38].The most common seed damage was caused by Ralstonia solanacearum.According to Sequeira & Graham [39] that the most dangerous bacterial disease is R. solanacearum which attacks in the early stages and cannot be detected with the naked eye.

Sprouting
The effect of varieties on sprouting during storage of potato tubers can be seen in Table 4. Bulbs began to sprout at week 6 and then increased in line with the increase in storage time.Potato tubers can be stored at room temperature.Bulbs stored at room temperature will germinate faster (Table 4).The storage room temperature was 22.20ºC and rH = 68.81%.In comparison, according to Beukema & Zaag [37], storage at 18 0 to 25 0 C tubers will sprout after 3 to 4 months.
Visual observations showed that tubers stored at room temperature began to germinate at week 6.Bulbs stored at room temperature germinated faster because of the high respiration process, resulting in an overhaul of food reserves.The reshuffle of food reserves will encourage shoot growth [40].Potato tubers will start sprouting after the dormancy period ends.The length of the potato dormancy period was influenced by the potato variety, the age of the tubers at harvest, the environmental conditions at planting and the storage conditions of the tubers [35] The dormancy period can be accelerated by storing the tubers at a higher temperature (18 0 to 25 0 C).The growth rate of shoots was thought to be due to tubers experiencing stress in the storage environment which will affect respiration activities and encourage shoot growth.The decrease in weight after sprouting becomes greater because the respiration and evapotranspiration processes will be higher.

Conclusion
Based on the highest number of parameters with good results, clones 16, Atlantic, Medians and AR-08 were recommended to be used as raw materials for potato chips and french fries processing industry.Clone 16 showed good result for 7 parameters (moisture content, starch content, reduction sugar, TSS, spesific gravity, weight loss, and rotten (%)).Atlantic showed good result for 7 parameters (moisture content, starch content, reduction sugar, spesific gravity, weight loss, rotten (%) and sprouting (%)).Medians showed good result for 7 parameters (moisture content, starch content, reduction sugar, TSS, spesific gravity, weight loss, and rotten (%)).AR-08 showed good result for 7 parameters (moisture content, starch content, reduction sugar, TSS, spesific gravity, rotten (%) and sprouting (%)).

Table 1 .
Effect of variety on moisture content, starch, reducing sugar and total soluble solid of potato tubers.

Table 2 .
Effect of variety on weight loss during storage of potato tubers.

Table 2 ,
the weight loss ranged from : 4.41 to 21.28%.The smallest weight loss was found in Medians (4.41%) but not significantly different with Atlantic and clone 16.The highest weight loss were found in clone AR-08 (21.28%) and clone 09 (17.39%) but not significantly different with clone 17 (14.14%)and clone 41 (18.31%).This difference in weight loss indicates that different clones have different shelf life.From Table

Table 3 .
Effect of variety on potato tuber rot during storage.

Table 4 .
The effect of varieties on sprouting during storage of potato tubers.