INTERNATIONAL JOURNAL OF RESEARCH AND SCIENTIFIC INNOVATION (IJRSI)  
ISSN No. 2321-2705 | DOI: 10.51244/IJRSI |Volume XII Issue XI November 2025  
Effect of the Ratio Between Corn Forage and Pineapple Peel Waste  
on Ph, Lactic Acid, Ammonia, and Organic Matter Changes in Silage  
Syahief Ariega1, Ujang Hidayat Tanuwiria2, Iin Susilawati1  
1Student at the Faculty of Animal Husbandry, Department of Animal Nutrition and Feed Technology,  
Padjadjaran University  
2Faculty of Animal Husbandry, Department of Animal Nutrition and Feed Technology, Padjadjaran  
University, Sumedang, Indonesia  
DOI: https://dx.doi.org/10.51244/IJRSI.2025.12110136  
Received: 30 November 2025; Accepted: 06 December 2025; Published: 19 December 2025  
ABSTRACT  
This study aims to evaluate the effects of different ratios of corn stover and pineapple peel waste on pH, lactic  
acid content, ammonia concentration, and changes in organic matter (OM) of silage as indicators of fermentation  
quality. The research was conducted using a Completely Randomized Design (CRD) with four treatments: P1  
(90% corn stover + 10% pineapple peel), P2 (80% + 20%), P3 (70% + 30%), and P4 (60% + 40%), each with  
five replications. The ensiling process lasted for 22 days under anaerobic conditions with the addition of 4%  
molasses. The results showed that variations in ingredient composition did not have a significant effect on pH,  
lactic acid content, or OM changes, but they had a significant effect on ammonia levels. The pH values ranged  
from 3.69 to 4.06, indicating stable fermentation. Lactic acid concentrations ranged from 1.30% to 1.46%, which  
is within the acceptable range for good-quality silage. Ammonia levels decreased as the proportion of pineapple  
peel increased, with the best results observed in P3 and P4, indicating lower protein degradation during  
fermentation. Changes in OM were relatively small across all treatments, reflecting consistent nutrient  
conservation efficiency. Overall, the combination of corn stover and pineapple peel waste was able to produce  
silage with good fermentation quality, with P3 and P4 providing the most optimal performance in reducing  
ammonia formation and maintaining organic matter integrity.  
Keywords: Corn Stover Silage, Pineapple Peel Waste, Fermentation quality, Ammonia Concentration, Organic  
Matter Change  
INTRODUCTION  
Improving the quality and quantity of feed is a key strategy for increasing the productivity of ruminant livestock.  
Feed plays an essential role in supporting the life functions of livestock. Therefore, innovation is needed in  
utilizing local resources, particularly through the use of agricultural waste as a high nutritional value feed  
ingredient. One commonly applied fermentation technology in feed processing is silage production  
(Chrysostomus et al., 2020). Silage is a feed preservation technique used to maintain and improve feed quality  
through anaerobic fermentation.  
The principle of silage production is the fermentation of forage by bacteria that predominantly produce lactic  
acid. Fermentation is carried out by homofermentative lactic acid bacteria as the environment transitions from  
aerobic to anaerobic conditions, resulting in lactic acid as the primary end product. The lactic acid produced  
through this process acts as a preservative, effectively inhibiting the growth of spoilage microorganisms.  
Nutritionally, the feed provided must meet the the standard requirements of livestock. Since it is closely related  
to intake and digestibility, the levels of dry matter and organic matter need to be carefully considered. A higher  
percentage of dry matter digestibility in feed ingredients indicates better nutritional quality (Sondakh et al.,  
2018).  
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INTERNATIONAL JOURNAL OF RESEARCH AND SCIENTIFIC INNOVATION (IJRSI)  
ISSN No. 2321-2705 | DOI: 10.51244/IJRSI |Volume XII Issue XI November 2025  
Agricultural waste, such as corn stover, contains high levels of fibre and carbohydrates and is easily accessible,  
making it one of the commonly used ingredients for silage production. However, corn stover is less optimal  
when used as a single ingredient due to its low crude protein content. Pineapple peel, which contains bromelain  
and vitamins, shows potential as an economical and high-quality alternative feed source. However, pineapple  
peel alone is insufficient to meet the nutritional requirements of ruminants. Therefore, additional protein-rich  
green feed derived from agricultural waste is required.  
This study aims to examine how silage formulations based on corn stover and pineapple peel waste affect pH,  
lactic acid concentration, ammonia levels, and changes in the organic matter of the silage. These issues indicate  
the necessity of conducting this research.  
MATERIALS AND METHODS  
Tools and Materials  
Several tools and ingredients as material used in this study included 90-day-old corn stover, chopped pineapple  
peel waste cut into 1–2 cm pieces, molasses, distilled water, 10-liter plastic jars, 40×60 cm plastic bags, an 8×6  
m tarpaulin, a vacuum sealer, a machete, clamp pliers, a scale, a pH meter, beaker glasses, titration equipment,  
drop pipettes, Conway dishes, Erlenmeyer flasks, an electric oven, a muffle furnace, aluminum dishes, porcelain  
crucibles, and a desiccator.  
Research Place  
The research was conducted at the Ruminant Animal Nutrition and Animal Feed Chemistry Laboratory, Faculty  
of Animal Husbandry, Padjadjaran University, from October to November 2025.  
Silage Production  
The ensiling procedure for corn stover and pineapple peel waste was carried out as follows: The pineapple peel  
waste was first chopped and wilted for 24 hours. Corn stover was then wilted for 2 hours. After wilting, the corn  
stover and chopped pineapple peel waste were mixed according to the treatment. Molasses diluted with water at  
a 1:1 ratio was added at 4% of the total material weight for each treatment. All ingredients were then thoroughly  
mixed. The mixed corn stover and pineapple peel waste were placed into plastic bags and vacuum-sealed. The  
sealed bags were then put into plastic containers, secured with adhesive tape, and fermented at room temperature  
for 22 days. After fermentation, the silage was removed and spread out. Samples of the silage were collected for  
the measurement of pH, lactic acid, ammonia content, and changes in organic matter.  
Variables Observed  
pH Silage  
The pH measurement was conducted to determine the acidity level of the silage as an indicator of successful  
fermentation. The samples that had completed the ensiling process were measured using a pH meter calibrated  
with pH 4 and pH 7 buffer solutions. This method allows for an accurate assessment of acidity under actual  
fermentation conditions, serving as an indicator of lactic acid fermentation dominance and silage stability.  
Lactid Acid  
Lactic acid was measured using the method described by Cappuccino and Natalie (1991). The principle of lactic  
acid determination is based on calculating the volume of NaOH used during titration, with the assumption that  
1 ml of NaOH corresponds to 9.008 g of lactic acid. The silage was mixed thoroughly, and a 10 g sample was  
placed into an Erlenmeyer flask, followed by the addition of 10 ml of distilled water. The sample was heated on  
a hot plate until the CO₂ was completely released. After cooling, five drops of phenolphthalein indicator were  
added to the solution. The sample was then titrated with 0.1 N NaOH until a light pink colour appeared.  
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INTERNATIONAL JOURNAL OF RESEARCH AND SCIENTIFIC INNOVATION (IJRSI)  
ISSN No. 2321-2705 | DOI: 10.51244/IJRSI |Volume XII Issue XI November 2025  
Ammonia (NH₃)  
Ammonia produced from papaya-stem silage was measured using the Conway microdiffusion method (General  
Laboratory Procedures, 1966). Before use, the rim of the Conway dish was coated with petroleum jelly. A 1 ml  
aliquot of the supernatant obtained from the fermentation process after 4 hours of incubation was placed on one  
side of the Conway dish groove, while 1 ml of saturated Na₂CO₃ solution was placed on the opposite side. The  
supernatant and the Na₂CO₃ solution must not be mixed at this stage. Asmall amount (1 ml) of boric acid solution  
with mixed indicators of bromocresol was placed in the central well of the dish. The Conway dish was then  
tightly sealed to ensure it was airtight. After sealing, the dish was gently shaken to allow the supernatant and  
Na₂CO₃ to mix thoroughly, and then left at room temperature for 24 hours. After this period, the boric acid  
indicator solution was titrated with 0.005 N H₂SO₄ until it turned reddish in colour.  
Organic Mattes Changes  
Changes in Organic Matter (OM) are widely used in silage research as an indicator of nutrient conservation  
efficiency, since organic matter represents the primary component utilised by microorganisms during  
fermentation. Losses in OM may result from initial respiration, microbial activity, or the disappearance of soluble  
solids throughout the fermentation process (Wróbel et al., 2023).  
The OM value is determined through ash analysis, in which the sample is combusted at 550°C until a constant  
weight is achieved. Organic matter is then calculated as 100% minus the ash content. Changes in OM are  
measured by comparing the initial OM content before fermentation with the final OM content after fermentation,  
following formulas commonly used in studies on mixed-forage silage (Mudhita et al., 2024).  
Data Analysis and Method  
This research employed an experimental method using a Completely Randomised Design (CRD) with four  
treatments, each replicated five times. The treatments were as follows:  
P1: 90% corn stover + 10% pineapple peel waste  
P2: 80% corn stover + 20% pineapple peel waste  
P3: 70% corn stover + 30% pineapple peel waste  
P4: 60% corn stover + 40% pineapple peel waste  
The observational data were analysed using Analysis of Variance (ANOVA). If the results showed a significant  
difference among treatments (P < 0.05), a post hoc test was conducted using Duncan’s Multiple Range Test at a  
5% significance level to determine differences between treatments.  
RESULT AND DISCUSSION  
Table I Effect of the Balance of Corn Stover and Pineapple Waste on pH, Lactic Acid, Ammonia and Changes  
in BO  
Parameter  
Treatment  
P1  
P2  
P3  
P4  
pH  
4,06 ± 0,06  
1,43 ± 0,21  
3,6 ± 0,22  
4,01 ± 0,06  
1,46 ± 0,11  
3,21 ± 0,31  
3,96 ± 0,02  
1,35 ± 0,14  
2,65 ± 0,27  
3,69 ± 0,03  
1,3 ± 0,07  
2,66 ± 0,43  
Lactic Acid  
Ammonia  
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INTERNATIONAL JOURNAL OF RESEARCH AND SCIENTIFIC INNOVATION (IJRSI)  
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Organic Matter Change  
0,3 ± 0,75  
-0,22 ± 0,69  
0,15 ± 0,71  
0,04 ± 1,08  
Data are presented as mean ± SD. All parameters showed no significant differences among treatments based on  
ANOVA (p > 0.05); therefore, superscript letters are not included. Note: P1 = 90% Corn stover + 10% pineapple  
peel waste; P2 = 80% Corn stover + 20% pineapple peel waste; P3 = 70% Corn stover + 30% pineapple peel  
waste; P4 = 60% Corn stover + 40% pineapple peel waste.  
pH  
The analysis of variance showed that the ratio of corn stover to pineapple peel waste had no significant effect on  
silage pH. The statistical analysis produced a p-value of 0.068, which is above α = 0.05, indicating that the  
differences in pH among treatments were not statistically significant. The four treatments (P1–P4) showed pH  
values ranging from 3.69 to 4.06, with an average of 3.93 ± 0.02. This range meets the criteria for good-quality  
silage and aligns with Hanifah et al. (2023), who reported that the optimal pH range for silage is approximately  
3.2–4.2 and that lower pH values are linked to lactic acid bacteria activity, better silage quality, suppression of  
spoilage microorganisms, and less nutrient loss during storage.  
The highest pH value was observed in P1 (4.06), followed by P2 (4.01), P3 (3.96), and P4 (3.69), the latter  
showing the highest acidity. Descriptively, a decreasing pH trend from P1 to P4 is evident, although the  
maximum difference is only around 0.37 pH units, which is relatively small in biological and technological  
terms. This suggests that the acid–base components in the silage matrix possess adequate buffering capacity,  
preventing substantial pH shifts despite the different treatment proportions. According to David et al. (2021), pH  
reduction occurs due to the increased population of microorganisms, especially lactic acid bacteria, which  
accelerate the ensiling process and consequently lower silage pH. Alower resulting pH indicates a more effective  
and stable ensiling and preservation process.  
The low pH values observed across treatments indicate that the fermentation process proceeded optimally, as  
lactic acid bacteria fermented soluble carbohydrates (derived from both corn stover and the simple sugars in  
pineapple peel) into organic acids that lowered the pH and inhibited spoilage microbes. Therefore, the  
combination of corn stover and pineapple peel waste has the potential to produce silage that is safe, stable, and  
has good storage durability for use as ruminant feed.  
Lactid Acid  
The analysis of variance showed that the ratio of corn stover to pineapple peel waste did not significantly affect  
lactic acid content (p = 0.278 > 0.05), with an average value of 1.39 ± 0.06. These indicate that varying the  
proportion of pineapple peel waste did not lead to significant differences in lactic acid concentration.  
According to Ranjhan (1980), high-quality silage typically contains 1.5–2.5% lactic acid. In this study, the lactic  
acid levels in P1 and P2 were slightly higher (approximately 1.4%) than those in P3 and P4 (approximately  
1.3%). Although these values are marginally below the upper threshold reported by Ranjhan, all treatments  
remained within the 1–2% range, which is classified as an indicator of proper silage fermentation. This level of  
lactic acid is sufficient to lower the pH to an acidic range and inhibit the growth of spoilage microorganisms.  
Farihah (2005) emphasizes that higher lactic acid levels are associated with improved silage quality, as increased  
lactic acid helps maintain a low pH, thereby enhancing silage stability and shelf life of the silage.  
The addition of pineapple peel waste provides a readily fermentable carbohydrate source (simple sugars), which  
act as substrates for lactic acid bacteria. However, the relatively uniform anaerobic conditions and comparable  
fermentation capacity across treatments likely resulted in stable lactic acid production. Pineapple peel also  
contains organic acids that help suppress the growth of aerobic bacteria. As stated by Jones et al. (2004),  
fermentation is a biologically mediated process in which lactic acid bacteria convert simple sugars into organic  
acids, predominantly lactic acid.  
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INTERNATIONAL JOURNAL OF RESEARCH AND SCIENTIFIC INNOVATION (IJRSI)  
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Ammonia  
The analysis of variance indicated that the ratio of corn stover to pineapple peel waste had a significant effect  
on silage ammonia content (p = 0.001 < 0.05), with values ranging from 2.65% to 3.60% (3.03 ± 0.09). These  
ammonia levels remain within the threshold of high-quality silage, in accordance with Kurnani (1995), who  
states that high-quality silage contains less than 11% ammonia of total nitrogen. Additionally, the results showed  
a clear decreasing trend in ammonia levels from P1 to P3 and P4, indicating that the inclusion of pineapple peel  
waste at appropriate proportions effectively reduced ammonia formation, which is associated with protein  
degradation during the fermentation process.  
Ammonia levels in P1 and P2 remained relatively higher compared to those in P3 and P4, which contained higher  
proportions of pineapple peel waste. At these higher proportions, pineapple peel appeared to better support the  
optimal growth of lactic acid bacteria, leading to a more rapid pH decline. The resulting acidic environment  
effectively inhibited the activity of proteolytic microorganisms responsible for ammonia formation. This  
observation aligns with Telleng (2017), who reported that a lower pH suppresses the growth of undesirable  
Clostridia bacteria that degrade protein.  
The addition of pineapple peel waste was therefore effective in reducing protein degradation in corn-stover  
silage, with P3 and P4 producing the best results. The lower ammonia levels observed in P3 and P4 indicate a  
more efficient fermentation process, better preservation of feed protein, and higher nutritional value of the silage  
for ruminant livestock. These findings are in line with Woolford (1984), who identified ammonia as an indicator  
of silage spoilage because it reflects protein breakdown and can increase silage pH.  
Organic Matter Change  
The results of the analysis of variance for the effect of corn stover–pineapple peel silage ratios showed relatively  
small variations in organic matter (OM) change, ranging from –0.22% to 0.30%, with an average change of 0.07  
± 0.19%. Statistical analysis indicated that the treatments had no significant effect on OM change (p = 0.790 >  
0.05). This suggests that the addition of pineapple peel waste at different levels did not produce significant  
differences in the OM content of the silage. This condition may be attributed to the natural sugars in pineapple  
peel, which serve as an energy source for lactic acid bacteria, being insufficient to maximize the fermentation  
process. This is supported by Khan et al. (2014), who stated that sugar content is a crucial factor for the  
development of lactic acid–producing bacteria during fermentation.  
The greatest OM loss occurred in P2 (–0.22%), while the smallest occurred in P4 (0.04%). The OM loss in P2  
may be associated with a portion of soluble carbohydrates being utilized as fermentation substrates by lactic acid  
bacteria. Conversely, P4 exhibited the smallest OM change, which practically indicates almost no difference  
between pre- and post-ensiling conditions. This suggests that at the highest pineapple peel proportion (P4), the  
integrity of organic matter was best preserved.  
Organic matter is determined by the difference between dry matter content and ash content. The ash content in  
silage reflects its mineral composition. A higher ash content indicates lower OM levels, whereas lower ash  
content corresponds to higher OM levels. Utomo (2015) states that OM content is influenced by several factors,  
including the rate of fermentation, wherein lactic acid bacteria work optimally when acidic conditions are rapidly  
established.  
CONCLUSIONS  
This study evaluated the effect of different ratios of corn stover and pineapple peel waste on silage quality,  
including parameters such as pH, lactic acid content, ammonia concentration, and changes in organic matter.  
The results showed that the variation in ratios did not significantly affect pH, lactic acid content, or changes in  
organic matter, but had a significant effect on ammonia levels. Increasing the proportion of pineapple peel  
reduced ammonia concentration and improved the fermentation process. Overall, the addition of pineapple peel  
waste proved effective in reducing protein degradation and preserving nutrients during fermentation, particularly  
in certain treatments, thereby producing high-quality silage suitable for ruminant feed.  
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INTERNATIONAL JOURNAL OF RESEARCH AND SCIENTIFIC INNOVATION (IJRSI)  
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ACKNOWLEDGMENT  
The authors gratefully acknowledge the financial support provided by Academic Leadership Grant (ALG) under  
Grant Number (3208/UN6.J/PT.00/2025). This support was instrumental in enabling the successful completion  
of this research project.  
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