Evaluation of physical quality, pH, fresh weight reduction and fungal percentage in citronella (Cymbopogon nardus) straw waste amofer

Research on citronella waste using Amofer technology (ammoniated fermentation) treatment was carried out to increase its nutritional content so that it becomes a quality alternative feed. Analysis of physical quality, pH, fresh weight and percentage of fungi in citronella waste used a completely randomized design divided into four treatments based on different fermentation times, namely P0 = day P1 = 7 days, P2 = 14 days and P3 = 21 days. The results showed that amofer treatment with different curing times affected the physical quality of citronella straw waste, P2 and P3 showed significant differences (P<0.05). Amofer treatment with curing for 21 days is able to degrade the essential aroma which is a limiting factor in the palatability level of livestock for feed.


Introduction
Utilizing citronella waste as an alternative substitute for forage for livestock is one of the motivations for providing limited forage for livestock during the dry season.Providing limited forage during the dry season can have an impact on livestock productivity.Therefore, the solution to overcome limited livestock forage in the dry season is to utilize this potential waste.Apart from being used as animal feed, citronella can also increase feed security, especially in the dry season, and also save labor in searching for grass [1].In an effort to increase the value of waste that has potential such as citronella, it is necessary to use feed processing technology that is easy, cheap and efficient and whose quality is maintained so as to increase the nutritional value of citronella waste.However, this type of waste has a low level of palatability due to its hard texture, so research needs to be carried out to test the changes that occur in citronella waste which is processed using the ammonia fermentation (amofer) method.

Materials and Methods
Research was carried out at the Livestock Field Laboratory (LLP) and the Forage and Feed Nutrition Laboratory.Department of Animal Husbandry, Faculty of Agriculture, Syiah Kuala University (USK) from 06 June to 19 July 2023.The design used in this research was a Completely Randomized Design (CRD).Where, 4 different treatments based on the length of curing days (P0 = 0 days, P1 = 7 days ; P2 = 14 days ; P3 = 21 days) with each treatment repeated 4 times to produce 16 treatment units.The initial stage of the research was carried out by chopping the citronella waste until it was 3-5 cm in size, then the entire sample was air-dried until the remaining water content was 10%.The samples were then tested for water content as an initial stage to determine the formulation when adding inoculants and prebiotics.Then proceed with the ammonia using urea as much as 3% stage for 7 days and fermentation with a long curing period guided by the research design that has been prepared using commercial inoculant MA-11 decomposer.
The variables observed in this research were: fresh weight reduction, pH, fungal percentage and physical quality (texture, color and odor) which were carried out using a scoring test.The physical quality data that has been obtained is then transformed into a numerical scale.The data obtained in the form of test results will be processed statistically using the SPSS program (version 16 for Windows).Data are presented as mean ± SE.If there are differences between treatments, proceed with the Duncan's Multiple Range Test according to [2].

Physical Quality of Citronella Waste Amophere
The results of observations on the amospheric texture of citronella waste showed that treatment P0 was the lowest treatment with a hard texture and treatment P3 was the best treatment with a soft texture, although it was not significantly different (P> 0.05) from treatment P2.This difference in texture is caused by the fermentation process in treatments P1, P2 and P3, as reported by [3] that in the fermentation process of palm oil leaves for ruminant feed with the help of lactic acid bacteria it can destroy organic materials such as lignin and cellulose, so the texture becomes softer.

Figure 1. Averaged of quality score
The results of observations on the color of the citronella waste amophere showed that treatments P1, P2 and P3 had different colors compared to treatment P0.Treatments P1, P2 and P3 had a brownish green color and treatment P0 had no color change.This happens because the fermentation process can cause a change in the color of citronella to brownish green as a result of the addition of MA11 decomposer bacteria.The results of this study are in line with [4] who reported that the addition of M21 decomposer bacteria at different levels in the fermentation process of corn comb as feed Ruminant livestock can change color to brownish.This color change indicates that the fermentation process has occurred very well.
The evaluation results of the amospheric aroma of citronella waste show that the P0 treatment has a different aroma from other treatments.The P0 treatment tends to have a distinctive aroma of essential oils and ammonia which is still very pronounced.Meanwhile, other treatments have a slightly sour aroma and still tend to have a slight aroma of essential oils and ammonia.The sour aroma that arises from the amospheric process is caused by the influence of lactic acid bacteria during the anaerobic fermentation process.In treatments P1 and P2, the essential aroma tended to decrease compared to P0, where the aroma was still very pronounced.Treatment P3 has the best score compared to treatments P1 and P2.The decrease in essential aroma was due to the influence of the fermentation process in treatments P1, P2 and P3, the essential aroma and ammonia also disappeared as the fermentation process progressed.This is in line with research reported by [5] which states that in the amospheric fermentation process of corn kernels where the ammonia produced from the ammonia process can be degraded by lactic acid bacteria and the fermentation process is declared to have taken place optimally.

Shrinkage Fresh Weight
The results of analysis of variance showed that there were significant differences (P<0.05) in fresh weight ( 0.00 a 0.00 a 0.00 a 15.31±4.27c [6] showed that there was a decrease in fresh weight in rice straw amofer with the highest average being -30.75.During the fermentation process, each type of substrate will show a different response.A decrease in the weight of fresh material can indicate that the metabolic process of microorganisms is running well, the microorganisms will respire by evaporating the water contained in the substrate so that the fresh weight will also decrease after the fermentation process is complete.

Averange of pH
The study found that the treatment of citronella waste without MA-11 Decomposer (P0) resulted in the highest pH of 7.21, while the lowest was in treatment 22, which had a pH of 4.46.P0, a control treatment, had the smallest number of decomposing bacteria, resulting in no effect on pH and causing the R0 treatment to have a higher pH.This aligns with [7] opinion that fewer lactic acid bacteria work as decomposers.Treatments P1, P2 and P3 are treatments that added MA-11 Decomposer and urea.The addition of MA-11 Decomposer and urea shows that the pH value decreases because the bacteria contained in MA-11, the Decomposer will be active through the fermentation process and produce lactic acid which results in lowering the pH.The decrease in pH is also caused by the presence of ammonia as a result of the ammonia process which functions as an energy source for bacteria.According to [8], the high and low pH is very dependent on the formation of lactic acid.[9] added that the rapid formation of lactic acid will be directly proportional to the increase in acidic conditions in the incubation room.
Another factor that causes a decrease in pH is the ammonia content which is useful as an energy source for lactic acid bacteria.Treatment P2 got a pH value of 4.46, which means the treatment tends to be the best.This shows that the fermentation process can take place optimally due to an increase in the amount of lactic acid produced from bacterial activity so that it can accelerate the decrease in pH.[10] stated that a low pH value indicates that enough lactic acid is produced so that it can accelerate the decrease in pH.[11] categorize fermentation quality based on fermentation pH, with 3.5-4.2being very good, 4.2-4.5 being good, 4.5-4.8being medium, and more than 4.8 being poor.Treatment P2 (4.46) results in a slight ammonia aroma, indicating that ammonia is widely used in the fermentation process, resulting in lower pH.[8] states that the slight ammonia smell in fermentation results is converted into lactic acid, causing a slight ammonia aroma.The more lactic acid produced, the lower the pH condition.

Percentage of Mold Presence
The percentage of fungal presence is measured based on the weight of the substrate on which the fungus grows divided by the initial weight of the substrate multiplied by 100%.This measurement was carried out to see the number of fungi growing in each treatment unit.Based on the results of observations (Table 1), treatments P0, P1 and P2 were not moldy except for P3, which means that fermentation in this treatment group was running perfectly.[12] states that successful fermentation is indicated by the absence of mold growing.In citronella waste amofer treated with the addition of MA-11 decomposer with a curing time of 21 days, the percentage of fungal growth was found to be 15.31 ± 4.27 c or 45.93 grams of substrate.
Fungal contamination was found in the corners of the silo, while there was no fungus on the inside.The fungus contained in the sample is white, this fungus is not toxic.In contrast to red and greenish mushrooms, this type has and poisonous properties [13].It is suspected that LAB is entering the death phase, LAB stops its growth due to decreased availability of water soluble carbohydrates (WSC).[14]) reported that fungal contamination occurred in king grass silage with the addition of onggok on days 14 and 28.The presence of fungus was closely related to the presence of air trapped in the silo, either in the initial phase of ensilage or due to silo leaks during storage.The density properties of citronella waste material affect the stability of the air during the fermentation process.The higher the density of the material will increase the level of silage compaction, as a result the air contained in the silo will be reduced [3].

Correlation of pH to Physical Properties
Based on a simple correlation test in table 2, it can be seen that pH has a moderate to strong correlation with several physical parameters of the citronella waste amosphere.pH has a moderate correlation to aroma and texture with r values of 0.551 and 0.485 respectively, which means that pH influences aroma and texture by 55.10% and 48.50% respectively.then 44.90% and 51.50% are other factors outside of observation.A strong correlation can be seen in the effect of pH on the presence of fungi with an r value of 0.630 or 63% of the pH value influences the level of fungal growth and the remaining 37% is an unobserved factor.This is based on the opinion of [15], that the correlation value of 0.60--0.799 is included in the strong category and the correlation value of 0.40--0.599 is included in the medium category (table 2.).

Conlusion
It can be concluded that the application of feed processing technology using the ammonia fermentation (amofer) treatment method on citronella waste has an effect on the physical quality and is able to significantly reduce the aroma of the remaining essential oil so that it is expected to have a good level of palatability as animal feed for livestock.

Table 1
) at different curing times.The P3 treatment with a curing period of 21 days showed the highest average shrinkage (-27.85 ± 2.11 b ) although it was not statistically different (P> 0.05) from P2 (-27.72 ± 1.52 b ).

Table 1 .
Averanged of fresh weight loss, pH and percentage of mold

Table 2 .
Correlation pH to physical quality