Effect of Saccharomyces cerevisiae on the quality of fermented jackfruit by-products

Nguyen Minh Thu¹, Tran Thi Thuy Hang² and Ho Thanh Tham¹

¹ Faculty of Animal Sciences, College of Agriculture, Can Tho University, Vietnam. Campus II, 3/2 Street, Ninh Kieu District, Can Tho City, Vietnam
httham@ctu.edu.vn
² Department Agricultural Technology, College of Rural Development, Can Tho University

Abstract

The experiment was conducted on fermented jackfruit by-products with Saccharomyces cerevisiae (SC) to evaluate its effects on the quality of jackfruit by-product (JBP) silages at 0, 7 and 14 days. The experiment was conducted from January to March 2024. The study was arranged in a completely randomized design with three treatments (T) and three replications. The treatments included: (T1) JBP + SC (2 g/kg JBP); (T2) JBP + SC (4 g/kg JBP); and (T3) JBP + SC (6 g/kg JBP). The results showed that the JBP silages in all treatments met the sensory evaluation requirements for color, odor and absence of mold formation. Among them, treatment T2 maintained the best color and texture after 14 days of fermentation, without any signs of softening, unlike treatment T3. The pH values of the treatments ranged from 3.90 to 4.13 at 14 days. The dry matter (DM) content of the JBP silages in the treatments was 13.2%–14.3%. At 14 days, the crude protein (CP) content of T2 and T3 was high, at 12.2% and 14.1%, respectively and lowest in treatment T1 (11.4%). The neutral detergent fiber (NDF) content of JBP silages in the treatments ranged from 45.7% to 59%. All treatments met the evaluation criteria for organic acid content in silage. The addition of Saccharomyces cerevisiae to JBP helped improve CP content and allowed storage for up to 14 days. However, treatment T2, with a supplementation level of 4 g Saccharomyces cerevisiae, was the most optimal choice, balancing silage quality and economic efficiency.

Keywords: Saccharomyces cerevisiae, silage, jackfruit, by-product

Introduction

At present, industrial livestock operations primarily rely on imported breeds, technology and feed components. This dependence exposes them to financial risks resulting from significant fluctuations in input costs, supplies and the market value of their final products (Nguyen Xuan Trach 2021). To reduce these economic risks associated with feed, the recent practice of utilizing by-products such as corn stalks, cashew shells and jackfruit peel for ruminants has contributed to boosting productivity and increasing economic efficiency for livestock farmers (Phan Van Sy et al 2021; Ngo Thi Kim Chi and Nguyen Duc Dien 2022).

The jackfruit ( Artocarpus heterophyllus Lam) is native to India and is widely grown in Southeast Asia (APAARI 2012). The peel of the jackfruit is a potential by-product in ruminant livestock farming, contributing to the reduction of livestock costs (Prusty et al 2024). The polyphenol content of jackfruit peel is higher than that of pineapple, pomegranate and orange peels, which contributes to its antioxidant effects (Meera et al 2018). The antioxidant properties of jackfruit are due to the presence of a phenolic acid known as caffeic acid. Caffeic acid has antibacterial properties and may prevent cardiovascular diseases (Magnani et al 2014). Jackfruit has anti-inflammatory, antibacterial, antifungal, antidiabetic, anthelmintic, hypotensive and anti-aging properties (Goswami 2011). Its anti-cancer and anti-aging properties are attributed to its lignans, isoflavones and saponins (Lee et al 2013).

However, the crude protein content in jackfruit peel is low, at 7.39%, which is lower than that of young jackfruit (10.3%) (Lam Phuoc Thanh 2021; Ngo Thi Kim Chi and Nguyen Duc Dien 2022). Maintaining a jackfruit garden involves several essential steps, including selecting high-quality tree varieties, planting at an appropriate density, providing adequate irrigation, applying fertilizers and performing regular pruning (Mai Duc Chung et al 2022). Jackfruit is pruned to remove diseased, deformed and ground-touching fruits to focus on growing large fruits (Tho Mong 2012). It can be observed that a significant number of young jackfruits are removed during the care process. In particular, for the jackfruit cultivar Thai, the phenomenon of black fiber appears mainly in the rainy season at the stage of 30-90 days after the completion of fruit development (Le Tri Nhan et al 2016).

According to Khong Tien Dung (2022), the classification of jackfruit is primarily based on the fruit's weight, shape and quality. The fruit must be round, evenly segmented, free from worms and partially subject to the purchasing trader’s decision. Farmers predominantly sell jackfruit to traders, accounting for 84% of the total output, while approximately 16% is sold directly to fruit orchards. Among the classifications, type 1 jackfruit fetches the highest price, at approximately 60,000 VND/kg, representing about 25% of the total harvested output. Type 2 jackfruit is priced at around 30,000 VND/kg, constituting about 30% of the total output.

Photo 1. Black fiber symptoms in jackfruit observed at different stages: (a) fruit set, (b) 10 days after fruit set, (c) 20 days after fruit set, (d) 30 days after fruit set, (e) 50 days after fruit set, (f) 70 days after fruit set and (g) 90 days after fruit set Source from Vo Thi Ngoc Ha (2023)

Jackfruit affected by pests or containing black fibers is sold at a low price, ranging from 1,000 to 2,000 VND/kg, accounting for about 25% of the total output. Most farmers discard this low-quality jackfruit or use it as feed for livestock. A survey on pest and disease conditions in jackfruit gardens in Hau Giang Province, a major jackfruit cultivation area in the Mekong Delta, revealed that approximately 98% of households’ gardens exhibited symptoms of black fiber disease, with severe cases accounting for 22% of the affected gardens (Mai Duc Chung et al 2022).

Silage is an anaerobic fermentation technique for raw green fodder with a high-water content (75-80%). The fermentation microorganism system produces lactic acid and a certain amount of other organic acids (McDonald et al 1991). The addition of Saccharomyces cerevisiae (SC) to animal feed can increase animal productivity and improve both the rumen microbial system and the intestinal system in cattle (Tran Hiep and Nguyen Thi Tuyet Le 2018; Tran Hiep et al 2021). Therefore, using yeast SC in silage rations from jackfruit by-products is crucial for enhancing the value of this source. It allows for an evaluation of the quality of jackfruit by-products and provides a scientific basis for formulating feed rations for livestock.

Materials and methods

Location and time

The experiment was conducted from January 2024 to March 2024 at the laboratory of Ruminant Animal Production Techniques, Faculty of Animal Sciences, College of Agriculture, Can Tho University.

Research Object

Jackfruit by-products included young jackfruit and black fibrous jackfruit, which were collected from farmers in the Chau Thanh District of Hau Giang Province. These by-products were collected, with rotten parts removed and sliced using a specialized cutting machine to a thickness of 0.3-0.5 cm.

Experimental design

The experiment was arranged in a completely randomized design with three treatments and three replications, with each replication consisting of one silage bag. Jackfruit by-products were mixed with yeast and placed into plastic bags for silage. The silage bags were evaluated for sensory and quality attributes after 0, 7 and 14 days of silage. In total, there were 3 treatments × 3 silage times × 3 replications = 27 silage bags.

The treatments (T) are as follows:

T1 (SC2%): JBP + SC (2 g/kg JBP)

T2 (SC4%): JBP + SC (4 g/kg JBP)

T3 (SC6%): JBP + SC (6 g/kg JBP)

The mass of the jackfruit by-product (JBP), with the addition of Saccharomyces cerevisiae (SC), was calculated on a fresh basis. The yeast SC was a commercial product presented in the form of small granules, with a yeast concentration of 10 ¹¹ cfu/g (Actisaf SC48, Phileo, France).

The mixture was weighed according to the corresponding ratio for each experiment, ensuring that the total mass of the mixture was 1.5 kg per bag. The mixture was thoroughly mixed and placed into silage bags with a capacity of 4 liters. It was tightly compressed, vacuum-sealed using a vacuum machine (Buffalo, GF439-02, UK), labeled with the corresponding formula symbol and stored in a cool, dry place.

Measurements

All treatments were evaluated based on sensory attributes like color, odor and absence of mold. Nutritional criteria, pH and organic acid content were also assessed. The bags from each evaluation period were mixed and sampled for analysis. The chemical composition of the experimental diet was determined, including dry matter (DM), crude protein (CP), total ash, crude fat (EE) and crude fiber (CF), according to AOAC (1990). Acid detergent fiber (ADF) and neutral detergent fiber (NDF) were measured using the method described by Van Soest et al (1991). The chemical composition of the treatments was calculated based on %DM. Organic acid content (acetic acid, propionic acid and butyric acid) was evaluated 15 days after ensiling. The organic acid content was analyzed in the fresh state using the following method: A 5 g fresh sample was extracted with deionized water at a ratio of 1:6 and shaken on a horizontal shaker at 150 rpm for 60 minutes. The sample was then centrifuged at 13,000 rpm for 10 minutes, filtered through a 0.4 μm filter and analyzed using high-performance liquid chromatography (HPLC) with a Shimadzu LC-2030 Plus model.

Data analysis

The experimental data was processed using the Microsoft Excel 2016. The statistical data was processed using the General Linear Model (GLM) of the Minitab 16.2 software. Tukey's pairwise comparisons were applied to determine differences between treatments at 5% significance (p<0.05).

Results and discussion

Sensory evaluation

The results indicated that all treatments met the sensory evaluation criteria for color, aroma, slight sourness and absence of mold. Initially, the silage bags were light yellow and exhibited a characteristic jackfruit aroma, with a slight but not overpowering sourness. The texture was both soft and firm, with no signs of mold. After 7 days, the silage bags had changed to a mix of dark yellow and light brown, with a slightly sour smell and a smooth texture. By 14 days, the silage bags were dark yellow with light brown, had a slightly sour odor and maintained a smooth texture. However, treatment T3 exhibited signs of softening.

Photo 2. Initial silage bags are labeled as (a), (b) and (c) for treatments TI, TII and TIII, respectively. The 7-day time point is labeled as (d), (e) and (f) for treatments TI, TII and TIII, respectively. The 14-day time point is labeled as (g), (h) and (i) for treatments TI, TII and TIII, respectively

The pH changes

The results shown in Table 1 indicated that the pH values of the treatments gradually decreased over the silage period (p<0.05). Initially, the pH values ranged from 5.23 to 5.69. By days 7 to 14, pH values had significantly dropped to between 3.90 and 4.27 across all treatments. At 14 days, the pH values for the SC4% (4.05) and SC6% (4.13) treatments were higher than those for the SC2% treatment (3.90). These results demonstrate that the pH values of all treatments met the standards for quality silage feed.

If the pH value was below 4.5, the silage was considered high quality; otherwise, the quality was deemed poor (McDonald et al 2022). According to Limin et al (2018), changes in pH are an important criterion for evaluating silage quality. Plant enzymes begin decomposing the feed early in the silage process. A significant drop in pH was observed after 7 days, attributed to the decomposition of lactic acids by microorganisms. This process is crucial for inhibiting the growth of harmful bacteria and preventing feed spoilage (McDonald et al 1991; Van et al 2015). Subsequently, the pH level continued to decline, falling below 4.5. This decrease was due to the high proportion of lactic acid in the silage, which has a greater H+ ion dissociation constant than other organic acids. The reduction in pH helped restrict mold development and lower protein content in the silage (Muck 1988).

Changes in dry matter (DM) content

The DM content of SC6% treatment was statistically significant during the silage period (p<0.05) (Table 2). The DM content was lower at both 7 days (13.8%) and 14 days (13.7%) compared to the initial time (15.1%). After 14 days, the DM content of all treatments ranged from 13.2% to 14.3%.

It was observed that the DM content of all treatments decreased slightly compared to the initial stage. This decrease could be attributed to the bagging of raw materials for silage, which led to the breakdown of plant cells, particularly carbohydrates. This breakdown process generated heat and converted nutrients in the feed into lactic acid and CO₂, resulting in a reduction in DM mass (McDonald et al 1991; An 2004). However, Mohammed and Ali (2021) found that the DM content of silage was greater than 25%, which mitigated the decrease in dry matter mass. Consequently, the addition of other ingredients helped enhance the DM content in the silage (Yin et al 2021; Nkosi et al 2024).

Changes in crude protein (CP) content

The CP content of the SC6% treatment increased over the silage period (p<0.05) (Table 3). Initially, the CP content of all treatments fluctuated until the 7th day. By day 14, the CP content of the SC4% and SC6% treatments reached 12.2% and 14.1%, respectively. These results indicate an improvement in the CP content of the ensiled jackfruit by-product. These findings were higher than those reported by Munishamanna et al (2020), who observed that the CP content of ensiled jackfruit by-product with yeast (Lactobacillus acidophilus and Saccharomyces boulardii) ranged from 9.32% to 9.59%.

The study’s findings were lower than those reported by De Sousa et al (2020), who achieved a CP content of 17.1% using SC to ferment jackfruit peel. This difference is attributed to variations in the quality of the input materials. The nutritional content of jackfruit by-products can vary depending on the region where they are harvested (Hau et al 2015). The use of SC yeast in silage diets made from fruit peels significantly improved the CP content (Dharumadurai et al 2011; Mondal et al 2012). SC yeast produces extracellular enzymes that decompose proteins, increasing the free amino acid content in the feed. Additionally, the yeast density increases during fermentation, providing a source of single-cell protein (Kutshik et al 2016).

Changes in fiber content

the CF content of the SC2% treatment (25.9%) was higher than that of the SC4% treatment (24.7%) and the SC6% treatment (20.6%). At 14 days, the CF content of the treatments ranged from 27.1% to 28.3%. The initial fluctuation in CF content may be due to the effects of the early fermentation process. Lactic microorganisms ferment sugars, producing lactic acid, which creates a strongly acidic environment that inhibits other microorganisms, including those that utilize CF (Nguyen Huu Van et al 2015; Limin et al 2018).

The acid detergent fiber (ADF) content of SC6% treatment at different silage times was statistically significant (p<0.05). Specifically, the ADF content at 7 and 14 days was 34.6%, which was higher than the initial value of 27.4%. By day 14, the ADF content across all treatments ranged from 29.7% to 34.6%. These findings are consistent with the results of Pham Bao Duy et al (2022), who reported similar ADF content in silaged corn stalks (34.3%), Ho Thanh Tham and Nguyen Minh Thong (2019), who observed 36% ADF in silaged sweet potato vines. At 14 days, the NDF content in treatments SC4% and SC6% was lower (45.7% and 46.5%, respectively) than in SC2% (59%), indicating better quality feed in these treatments. According to McDonald et al (1991), the silage process promotes the growth of lactic microorganisms that produce enzymes to decompose hemicellulose, the main component of NDF. Once the pH reaches a certain level, these microorganisms can soften and decompose hemicellulose.

Changes in organic acid

The organic acid content of the treatments differed significantly (p < 0.05) (Table 5). The SC6% treatment had the lowest butyric acid content (0.09%) and the highest acetic acid content (0.28%). The SC4% treatment recorded a propionic acid content of 0.06%. In contrast, the SC2% treatment exhibited the highest butyric acid content (0.18%).

According to AOAC (2002), silage quality is considered good if the butyric acid content is less than 0.5%. Similarly, a silage batch is deemed good if the propionic acid content is below 0.5% and the acetic acid content does not exceed 2.5% (McDonald et al 1991). The results indicated that all treatments met the criteria for assessing the quality of organic acids.

Conclusions

The experimental results demonstrated the effectiveness of using Saccharomyces cerevisiae (SC) to improve the quality of fermented jackfruit by-products. All silage formulations met the sensory evaluation standards for feed. After 14 days, the CP content of the jackfruit silage increased significantly, while the NDF content decreased. The most optimal choice was treatment T2, which provided a balanced improvement in silage quality and economic efficiency with the supplementation of 4 g SC. These findings offer a practical basis for using jackfruit silage by-products as animal feed, contributing to enhanced productivity and cost savings in livestock farming.

Acknowledgments

This study was partly funded by Can Tho University (Code: TĐH2023-03). We also extend our gratitude to Phileo Vietnam Company for providing the yeast used in this research.

References

AOAC 1990 Official methods of analysis. Association of Official Analytical Chemists. 15th edn, Washington, DC.

AOAC 2002 Official methods of analysis of AOAC International. 17th edition. 1st revision. Gaithersburg, MD, USA, Association of Analytical Communities.

APAARI 2012 Jackfruit Improvement in the Asia-Pacific Region – A Status Report. Asia-Pacific Association of Agricultural Research Institutions, Bangkok, Thailand, 182 pages.

De Sousa A P M, Campos A R N, Gomes J P, De Santana R A C, De França Silva A P, De Macedo A D B and Costa J D 2020 Protein enrichment of jackfruit peel waste through solid-state fermentation. Revista Brasileira de Ciências Agrárias, 15(1): 1-6. DOI: 10.5039/agraria.v15i1a6406

Dharumadurai D, Subramaniyan L, Subhasish S, Nooruddin T and Annamalai P 2011 Production of single cell protein from pineapple waste using yeast. Innovative Romanian Food Biotechnology, 8(3): 26-32.

Goswami C C 2011 Physicochemical parameters of jackfruit (Artocarpus heterophyllus) seeds in different growing areas. Clinical Biochemistry, 13(44): S234.

Ho Thanh Tham and Nguyen Minh Thong 2019 The effect of different levels of sweet potato vine silage in the diet to the productivity of beef cattle. Journal of Animal Husbandry Sciences and Technics, 246: 68-72.

Khong Tien Dung 2022 Research for solutions for improving the value chain of jackfruit in Hau Giang province. Hue University Journal of Science: Economics and Development, 131(5C): 83–101. DOI: 10.26459/hueunijed.v131i5C.6494

Kutshik J, Usman A and Ali-Dunkrah U 2016 Comparative study of protein enrichment of lignocellulose wastes using baker’s yeast (Saccharomyces cerevisiae) for Animal Feeds. Journal of Biotechnology and Biochemistry, 2(7): 73-77.

Lam Phuoc Thanh, Nguyen Thi Thu Ha, Duong Tran Tuyet Mai, Vo Thi Phuong Tien, Nguyen Chau Khanh Van and Tran Thi Thuy Hang 2021 Effect of jackfruit leaves and young jackfruits by-product on in vitro ruminal fermentation and methane production. CTU Journal of Science, 57(6): 104-114.

Le Tri Nhan, Tran Thi Doan Xuan, Tran Van Hau and Tran Sy Hieu 2016 Flowering characteristics, fruit development and appearance of the ‘black fiber’ phenomenon on jackfruit ( Artocarpus heterophyllus Lam.) cv. ‘Thai’ grown at Cai Rang district, Can Tho city. CTU Journal of Science, 3: 79-87. DOI: 10.22144/ctu.jsi.2016.073

Le Van An 2004 Sweet potato leaves for growing pigs: Biomass yield, digestion and nutritive value. Doctoral thesis, Swedish University of Agricultural Sciences, Uppsala.

Lee P R, Tan R M, Yu B, Curran P and Liu S Q 2013 Sugars, organic acids and phenolic acids of exotic seasonable tropical fruits. Nutrition & Food Science, 43(3): 267-276.

Limin K J, Shaver R, Grant R and Schmidt R 2018 Silage review: Interpretation of chemical, microbial and organoleptic components of silages. Journal of Dairy Science, 101(5): 4020-4033.

Magnani C, Isaac V L B, Correa M A and Salgado H R N 2014 Caffeic acid: A review of its potential use in medications and cosmetics. Analytical Methods, 6(10): 3203-3210.

Mai Duc Chung, Tran Hong Duc, Nguyen Thi Kieu, Nguyen Duy Phuong, Nguyen Thanh Ha, Nguyen Xuan Canh, Nguyen Van Giang, Pham Hong Hien, Nguyen Hai Yen and Nguyen Thanh Duc 2022 Pests and diseases survey on jackfruit trees in Hau Giang province. Vietnam Journal of Science and Technology, 6(139): 79-86.

McDonald P, Edwards R, Greenhalgh J, Morgan C A, Sinclair L A Wilkinson R 2022 Animal Nutrition. Eighth Edition. Pearson Education Limited, Harlow, England.

McDonald P, Henderson A and Heron S J E 1991 The biochemistry of silage. Chalcomhe Pubhcations, UK, 340 pages.

Meera M, Ruckmani A, Saravanan R and Lakshmipathy P R 2018 Anti-inflammatory effect of ethanolic extract of spine, skin and rind of Jack fruit peel – A comparative study. Natural Product Research, 32(22): 2740-2744.

Mohammed S K and Ali A S 2021 Effect of dry matter levels and source of soluble carbohydrate on quality and nutritive value of corn stover silage. Euphrates Journal of Agriculture Science, 13(4): 63-72.

Mondal A K, Sengupta S, Bhowal J and Bhattacharya D 2012 Utilization of fruit wastes in producing single cell protein. International Journal of Science, Environment and Technology, 1(5): 430-438.

Muck R 1988 Factors influencing silage quality and their implications for management. Journal of Dairy Science, 71(11): 2992-3002.

Munishamanna K, Ajey G, Veena R and Palanimuthu V 2020 Evaluation of Different Strains of Yeast and Lactic Acid Bacteria for Nutritional Improvement of Jackfruit Waste Under Solid State Fermentation. Mysore Journal of Agricultural Sciences, 54(2): 44-50.

Ngo Thi Kim Chi and Nguyen Duc Dien 2022 The effects of composted jackfruit fiber and peel on the growth of BBB crossbred cattle in Dak Lak. Journal of the Faculty of Animal Science and Veterinary Medicine - Tay Nguyen University, 52: 8-11.

Nguyen Huu Van, Nguyen Thi Mui, Nguyen Song Toan, Nguyen Xuan Ba and Nguyen Tien Von 2015 Investigation into the creation of Fermented Mixed Feed (FTMR) from high-fiber agricultural waste for beef cattle: I. An examination of the quality of FTMR feed generated from various by-products. Agriculture and Rural Development – Hue University Journal of Science, 22(2): 92-98.

Nguyen Xuan Trach 2021 Development of sustainable livestock production based on high-tech application: Optimised benefits with minimised risks. Huaf Journal of Agricultural Science & Technology, 5(3): 2624-2632.

Nkosi B D, Malebana I M, Rios S Á, Nkukwana T T and Meeske R 2024 Ensiling of High-Moisture Plant By-Products: Fermentation Quality, Nutritional Values and Animal Performance. Fermentation, 10(8): 426.

Pham Bao Duy, Bui Thi Thu Huyen, Nguyen Thien Truong Giang, Vu Minh Tuan and Bui Viet Phong 2022 Effects of use of biomass maize silage in ration of beef cattle. Journal of Animal Husbandry Sciences and Technics, 283: 55-59.

Phan Van Sy, Dau Van Hai, Doan Vinh, Vu Minh, Dau Huynh Bao and Nguyen Van Phu2021 Investigation into the utilization of fermented cashew nuts as fodder for beef cattle. Journal of Animal Science and Technology, 125: 40-47.

Prusty S, Gendley M, Singh A, Dubey M, Patil P and Sharma V 2024 Jackfruit waste and peels: Potential as livestock feed. The Indian Journal of Animal Sciences, 94(5): 395-400.

Tho Mong 2012 The process of nurturing and cultivating jackfruit trees. Binh Duong Science and Technology, 5: 28-32.

Tran Hiep and Nguyen Thi Tuyet Le 2018 Utilization Of Fermented Liquid Forages for Growing Pigs. Vietnam Journal of Agricultural Science, 16(5): 439-447.

Tran Hiep, Nguyen Xuan Hoang Vu Thi Trang, Nguyen Thi Tuyet Le and Pham Kim Dang 2021 Effect of Probiotic Cell Wall Supplement on some Technical-Economic Indicators of Growing-fattening Pigs. Vietnam Journal of Agricultural Science, 19(12): 1598-1607.

Tran Van Hau , Pham Thanh Sang and Tran Thi Doan Xuan 2015 Effect of doses of N-P2O5-K2O-MgO composition on yield and quality of the sterile-seeded ‘Ba Lang’ jackfruit in Cai Rang District, Can Tho City. CTU Journal of Science, 36: 63-71.

Van Soest P J, Robertson J B and Lewis B A 1991 Methods for dietary fibre, neutral detergent fibre and non-starch polysaccharides in relation to animal nutrition. Journal of Dairy Science, 74(10): 3583-3597.

Vo Thi Ngoc Ha 2023 Investigation of current status and disease progress of bronzing on “Thai” jackfruit (Artocarpus heterophyllus Lam.) in Tien Giang province. The Journal of Agriculture and Development – Nong Lam University, 22(2): 11-22.

Yin X, Wu J, Tian J, Wang X and Zhang J 2021 Dried soybean curd residue: A promising absorbent for cleaner production of high-quality silage. Journal of Cleaner Production, Volume 324, Article #129300 Retrieved January 9, 2025, from https://doi.org/10.1016/j.jclepro.2021.129300