The process of making green melinjo fruit peel extract powder drink with the addition of egg white and palm sugar as material from Indonesia local resources

An instant powder drink made from green melinjo fruit peel extract with egg white and palm sugar is expected to become diversify food also beneficial for health. Palm sugar contains secondary metabolite compounds which function as antioxidants for powder drinks and sustainability of food for supporting food security. The purpose of this study was to determine the effect of the addition of egg white and palm sugar on the characteristics of green melinjo fruit peel extract powder drink. This study used a CRD (Completely Randomized Design) factorial method with 2 factors, such as egg white percentage of 25%, 30% and 35%, and palm sugar percentage of 5%, 10% and 15%. The results showed that the addition of egg white had a highly significant (P <0.01) effect on antioxidant activity, dissolving rate, and total flavonoids. The addition of palm sugar had a highly significant (P <0.01) effect on antioxidant activity, dissolving rates, and total flavonoids. The result showed that the best treatment was M3S3 (35% egg white and 15% palm sugar), which gave the hinger total flavonoid content (12.9133 mg EQ/g) and higher dissolving rate (54.6667 g/second).


Introduction
Melinjo (Gnetum gnemon L.) plant is a type of gnetum plant that has many benefits for its seeds, peels and leaves.Melinjo peel is often separated and rarely used as food product.Melinjo peel contains many nutritional values such as ascorbic acid, tocopherols, polyphenols which have antioxidant activity.Melinjo producing areas in the province of North Sumatra specifically Deli Serdang district [1].
The results of research [2], proved that melinjo fruit peel extract has great potential to inhibit free radicals.Melinjo peel extracted using 70% ethanol also produces antioxidant activity can inhibit tumor growth.Melinjo peel has potential as an antidiare.Several active compounds in melinjo peel such as tannis, triterpenes and terpenes can function as antidiare, Melinjo peel has phytochemical components, which can reduce uric acid [3].One alternative to consume melinjo peel is by processing it into a powder drink that can increase economic value and sustainable food products.According to [4], the powder drink form has the advantages of being smaller in volume to facilitate packaging and become long lasting product.Palm sugar as food ingredient can support the sustainability of local food products which is useful for giving the powder drink a good taste and distinctive aroma.Palm sugar also contains secondary metabolites in the form of saponins, phenols, triterpenoids and alkaloids which can increase the content of antioxidant activity and good for health.
Foam mat drying is a simple method for drying solids in liquid by mixing them with a foaming agent to produce stable foam, by using oven drying at 50-80•C.Drying temperature is one of the external factors that affect product quality.If the drying temperature used is too high, it will cause a decrease in nutritional value and discoloration of the product after being dried with the treatments of certain temperature [5].Foam-mat drying is useful for producing dry products from liquid material that are sensitive to heat or contain high sugar content.The success of foam-mat drying is largely determined by the foaming agent used.One of the foaming agents that is often used is egg white because it is natural, easy to obtain, and cheap [6].According to [7], the use of egg whites with the right concentration gave a porous structure and increase the surface area that affect the drying rate.The objective of these research was to determine antioxidant activity, flavonoid content and the dissolved rate of the melinjo green fruit peel extract powder drink by added palm sugar.

Production of green melinjo fruit peel extract powder
The part of the melinjo plant that is used includes the young melinjo fruit (green peel).Every part of the melinjo washed thoroughly.The melinjo seeds were first peeled before being crushed.The extraction process was carried out by heating to 60•C by immersing the sample with stirring on a hotplate.The extraction process was carried out with a ratio of materials and solvents in a ratio of 1:20 at 60•C for 30 minutes.The solvent used in the melinjo extraction process is aquadest with a ratio of 1:20 (green melinjo fruit peel : distilled water).After heating at 60•C, the solvent and sample mixture is cooled down to room temperature.Filtering is used to separate the dregs (sediment) and filtrate.The filtering process of green melinjo fruit peel extract is carried out using a filter cloth and then the foam mat drying method is carried out.Then the green melinjo fruit peel extract was obtained from the filtering results and used for the extract powder preparation.Extract powder preparation is done by using 300 ml of melinjo fruit peel extract and added egg white with 3 percentage levels (25%, 30%, 35%) then added palm sugar as a sweetener with 3 percentage level (5%, 10% and 15%) and fillers maltodextrin as much as 15%, then mixed for 15 minutes until it forms foam then dried the foam by placing it on a baking sheet using a cabinet dryer or blower oven at 70•C for 12 hours.After that, it was sifted using an 80mesh sieve.Then obtained melinjo fruit peel extract powder, and then carried out several tests [8].

Quality parameters
Antioxidant activity is measured using DPPH methods [9].Total flavonoid levels were analyzed by Calorimetric assay using AlCl3 and quercetin standard [10].The dissolution time was determined by the level of solubility instant drink powder in water when consumed, and then analysis of the dissolution time was carried out.In this study, the dissolution time test was carried out by weighing 5 g of the material and then the sample was dissolved in 100 ml of water in a beaker glass.After that, the dissolution rate of the instant powder functional drink was calculated in units of time (s) [11].

Antioxidant activity
The addition of egg whites had a highly significant (P<0.01)effect on the antioxidant activity of green melinjo fruit peel extract powder drink.The results of LSR test and the graph of the relationship between the addition of egg white and antioxidant activity can be seen in Figure 1.

Figure 1. The effect of egg white addition on antioxidant activity
From Figure 1, the higher the addition of egg white can cause the decrease of IC50 produced from green melinjo fruit peel extract powder drinks, which means the antioxidant activity increases.This is because the higher egg white added, the foam produced will be much more.According to [12], the high free radical scavenging activity in instant powder is not due to the addition of egg white but egg white function as a foam agent to rate up the drying process so it does not damage the important compounds of the dried material.
The addition of palm sugar had a significant effect (P<0.05) on the antioxidant activity of green melinjo fruit peel extract powder drink.The results of LSR test and the graph of the relationship between the addition of palm sugar and antioxidant activity can be seen in Figure 2. From Figure 2, the higher addition of palm sugar can cause the decrease of IC50 produced from green melinjo fruit peel extract powder drinks, which means the antioxidant activity increased.IC50 is a value that shows the ability to inhibit free radicals by 50%.According to [13] there are several categories of IC50, if IC50 is below 50 ppm shows the antioxidant activity is very strong, 50-100 ppm (strong), 100-150 ppm (medium), 150-200 ppm (weak) and greater than 200 ppm shows the antioxidant activity is very weak.The addition of palm sugar can increase the antioxidant activity of a material because palm sugar contains secondary metabolites in the form of saponins, phenols, triterpenoids and alkaloids [14].
The interaction of adding egg white and palm sugar had no significant different (P>0,05) effect on the antioxidant activity of green melinjo fruit peel extract drink powder so the LSR test was not continued.

Total Flavonoids
The interaction of adding egg white and palm sugar had a highly significant (P<0.01)effect on the total flavonoids of green melinjo fruit peel extract powder drink.The highest effect was found in the M3S3 12.9133 mg EQ/g and the lowest total flavonoids was found in M1S1 5.6600 mg EQ/g.The results of LSR test and the graph of the interaction between the addition of egg white and palm sugar with the total flavonoids can be seen in Figure 3.
Figure 3.The interaction between the addition of egg white and palm sugar with total flavonoids of green melinjo fruit peel powder drink From Figure 3, the higher addition of egg whites added and the greater the percentage of palm sugar, the total flavonoids of the green melinjo fruit peel extract drink produced increased.This is due to the interaction between egg whites and palm sugar.Egg whites function as protecting bioactive compounds from palm sugar such as melanoidin which is formed during heating in the process of making sugar and green melinjo fruit peel extract by producing a lot of foam.

Dissolving rate
The interaction of adding egg white and palm sugar had a highly significant (P<0.01)effect on the dissolving rate of green melinjo fruit peel extract powder drink.The highest dissolving rate was found in the M3S3 54.6667 g/second and the lowest dissolving rate was found in M1S1 76.6667 g/second.The results of LSR test and the graph of the interaction between the addition of egg white and palm sugar with the dissolving rate can be seen in Figure 4.

Figure 4.
The interaction between the addition of egg white and palm sugar with dissolving rate of green melinjo fruit peel powder drink From Figure 4, the higher the addition of egg white the lesser the dissolution time required and also the higher addition of palm sugar caused the decrease of soluble time required by green melinjo fruit peel extract powder drink.This was due to the interaction between egg white which function as a foam mat drying to increase the surface area so that the structure of the powder drink is more porous [15].Where as in palm sugar there is sucrose which is soluble in water so that the required dissolution time lesser.

Conclusion
The addition of egg whites had highly significant (P<0,01) effect on antioxidant activity, dissolving rate, total flavonoids.The addition of palm sugar had a highly significant (P<0,01) effect on antioxidant activity, dissolving rate, total flavonoids of green melinjo fruit rind extract powder drink.The interaction between the addition of egg white and palm sugar had a highly significant (P<0,01) effect on dissolving rate and total flavonoids in green melinjo fruit rind extract powder drink.The best quality result for green melinjo fruit peel powder drink was obtained in the M3S3 treatment.The assessment was obtained based on the highest antioxidant and flavonoid activity content, these components were good for health and have great potential to inhibit free radicals and based on the low dissolving rate time which is the good quality of the powder drink can be seen from the powder can dissolve quickly in water.

Figure 2 .
Figure 2. The Effect of palm sugar addition on antioxidant activity