Subscribe Now Subscribe Today
Research Article
 

Potential of Waste Tea Leaves (Camellia sinensis) in West Sumatra to Be Processed into Poultry Feed



Wingki Ari Angga, Yose Rizal, Maria Endo Mahata, Ahadiya Yuniza and Reni Mayerni
 
Facebook Twitter Digg Reddit Linkedin StumbleUpon E-mail
ABSTRACT

Background and Objective: West Sumatra is the third largest tea-producing area in Indonesia. Tea plantations in this area produce top quality leaves that can be marketed both domestically and internationally. To maintain a high level of tea leaf productivity, plants should be pruned every 3 years using a rotation system that involves monthly prunings. These prunings produce waste tea leaves that can serve as alternative feed resource for poultry as they have good nutritional value. Tea leaves contain high concentrations of antioxidants, such as polyphenols and policosanol as well as minerals and vitamins, which are known to improve poultry health. Unfortunately, tea leaves also contain high levels of tannins and crude fiber-components known to be detrimental to poultry. This study was designed to evaluate the potential of waste tea leaves (Camellia sinensis) as poultry feed in West Sumatra by reducing their tannin content through immersion in fresh and hot water. Materials and Methods: This research consisted of two phases. The first phase was a survey of the potential of waste tea leaves as poultry feed through interviews and measurement of waste tea leaf production. The second phase was to experimentally process waste tea leaves through immersion in fresh and hot water. Variables measured during phase 1 included the size of tea plantations, ownerships, tea varieties produced, waste tea leaf production and estimated potential for poultry feed. The experiment conducted in phase 2 was performed using a completely randomized design involving 2×4 factorial arrangement of treatments with 4 replicates. The first experimental variable was water temperature (room temperature or 80°C). The second experimental variable was based on immersion at 6, 12, 18 or 24 h. Response variables measured included change in tannin content, dry matter (DM), organic matter (OM), crude protein (CP) and crude fiber (CF). Results: The results of the first phase indicated that the area of tea plantations in West Sumatra was 4,246.6 ha, ownership consisted of small holders (2,172 ha), the government (604.58 ha) and a private company (1,470 ha), total waste tea leaf production was 25,208.28 t/year, tea varieties or clones were Camellia sinensis assamica TRI 2024 and assamica TRI 2025 and waste tea leaves had the potential to feed 4,201,380,000 laying hens. The results of the second phase indicated that there was an interaction between water temperature and immersion duration on tannin reduction (p<0.05). Water temperature significantly influenced (p<0.01) reductions in OM and CP content and significantly affected (p<0.05) CF augmentation. Immersion duration significantly affected (p<0.05) DM reductions and highly significantly influenced (p<0.01) reductions in OM and CP. Conclusion: Waste tea leaves can be immersed in hot water (80°C) for 12 h to reduce their tannin content without affecting their protein content.

Services
Related Articles in ASCI
Similar Articles in this Journal
Search in Google Scholar
View Citation
Report Citation

 
  How to cite this article:

Wingki Ari Angga, Yose Rizal, Maria Endo Mahata, Ahadiya Yuniza and Reni Mayerni, 2018. Potential of Waste Tea Leaves (Camellia sinensis) in West Sumatra to Be Processed into Poultry Feed. Pakistan Journal of Nutrition, 17: 287-293.

DOI: 10.3923/pjn.2018.287.293

URL: https://scialert.net/abstract/?doi=pjn.2018.287.293
 
Received: November 20, 2017; Accepted: March 16, 2018; Published: May 15, 2018


Copyright: © 2018. This is an open access article distributed under the terms of the creative commons attribution License, which permits unrestricted use, distribution and reproduction in any medium, provided the original author and source are credited.

INTRODUCTION

Indonesia is the 5th largest tea producer in the world after Sri Lanka, Kenya, India and China, with levels of production reaching 154,598 t/year. This quantity of tea is grown on an area of only 118,441 ha1. Tea plants are shrubs or small trees that originate from the mainland of East Asia, the Indian subcontinent and Southeast Asia but are now cultivated throughout the world in both tropical and subtropical regions. Left to grow naturally, tea plants can become trees of 6 to 10 m in height2. Cultivated tea plants are often subjected to periodical pruning to a height of 1 m in order to facilitate leaf harvest and to maintain high levels of productivity.

Tea plant pruning is performed every 3 years to keep the plants in a vegetative state3. This pruning is employed because tea plants older than 3 years will produce smaller leaves and fewer shoots, decreasing the economic value of the tea crop4. The process of trimming tea plants produces leaves that are wasted and usually cover the growing shoots. Therefore, it would be more profitable to use trimmed tea leaves as feed for animals, especially poultry, given that tea leaves contain essential nutrients. This approach could reduce the use of commercial ingredients that are relatively expensive-feed costs often constitute 60-70% of the total cost of poultry production5.

Tea leaves have fairly high nutritional value and contain antioxidant compounds (polyphenols) that can improve poultry health6. According to Cabrera et al.7 the chemical composition of tea leaves is very complex. They have been found to contain crude protein (15-20% d.wt.), amino acids, such as theanine, aspartic acid, tyrosine, tryptophan, glycine, serine, valine, leucine and arginine (1-4% d.wt.), carbohydrates, such as cellulose, pectin, glucose, fructose and sucrose (5-7% dry weight), fat in the form of linoleic and linolenic acids, sterols in the form of stigmasterol, vitamins B, C and E, xanthic bases, such as caffeine and theophylline, pigments, such as carotenoids and chlorophyll, volatile compounds, such as aldehydes, alcohols, lactones, esters and hydrocarbons and minerals and other elements such as Ca, Mg, Mn, Fe, Cu, Zn, Mo, Se, Na, P, Co, Sr, Ni, K, F and Al (5%). Tea leaves also contain other compounds, such as carotenoids, which can lower cholesterol levels in the blood8.

The utilization of tea leaves as poultry feed is limited by the high content of crude fiber (26%7) and tannins that can impede the absorption of nutrients. Tannin content in tea leaves ranges from 7-15%9. Tannin is a secondary metabolite compound in plants and belongs to a group of polyphenol compounds that can form complex compounds with other molecules, such as carbohydrates and proteins, in the digestive tract to impede their absorption10. According to Wiharto11, the tolerance limit of crude fiber content in poultry feed is 4-5% and the maximum tannin content is 0.3%12. Muharlien13 reported that the addition of 2% green tea leaves to laying chicken diet lowered the cholesterol levels of egg yolks. In another experiment by Anita et al.14, old tea leaves were added to chicken diet at levels of up to 4.5% without affecting the performance of the poultry.

One of many ways to reduce the content of anti-nutritional substances is to subject the tea leaves to immersion12,15. According to Kawamoto et al.16, tannins are soluble in glycerol, water, hydro alcohol and alcohols. Meanwhile, Goodarznia and Govar17 found that the best method of extraction is to immerse leaves in hot water (130°C) for 10 min and generate a mass of 0.1800 g of catechin. Oematan18 reported that immersing cashew leaves in hot water (80°C) for 20 min can decrease their levels of tannin by 11.28%. Subandriyo and Setianingsih19 reported that the best method for tannin extraction in mangrove fruit is immersion in hot water (80°C) for 60 min.

Based on the above evidence, there seems to be an opportunity to utilize the waste tea leaf byproducts from tea plantations because pruned tea leaves still have good nutritional value. This research therefore, aimed to ascertain the importance of hot water immersion at different h on nutritive value of waste tea leaves.

MATERIALS AND METHODS

Experiment 1 (Survey potency of wasted tea leaves): The survey of the availability of waste tea leaves from tea plantations was performed in West Sumatra province, Indonesia from 20, February-25, March, 2017 on lands owned by small holders, the government and a private company. Data were collected through personal interview and observation.

Interviews: Interviews were performed to obtain secondary data from each tea plantation owner, such as the size of the tea plantation area, the rate of waste tea leaf production, the ownership of the tea plantation (small holder, government or private company), the varieties of tea planted and the cycle of tea pruning performed.

Observation: Waste tea leaf production was quantified by weighing pruned tea leaves. The tool used to measure tea leaves in a sample area was a 1 m2 quadrant, which was randomly placed at 9 points within the tea plantation. The tea leaves within the quadrant area were pruned by knife and then weighed. The weight of tea leaves in each of the 9 quadrants was summed and subsequently divided by 9 to obtain the average tea leaf production in every 1 m2. Finally, the tea leaf production per hectare was calculated by multiplying the average tea leaf production in a 1 m2 by 10,000.

Experiment 2 (Immersion of waste tea leaves in fresh and hot water):. This experiment was conducted at the non-ruminant laboratory of University of Andalas, Padang City, West Sumatera province, Indonesia.

Preparation for immersion of waste tea leaves: Before immersion, waste tea leaves were sun dried to obtain their dry weight. Water was heated using a hot plate. Water temperature was measured by thermometer until it reached 80°C. Dry waste tea leaves were divided into units of 100 g and then put into jars for immersion according to their assigned treatment for 6, 12, 18 and 24 h.

Response variables: Tannin content was measured by Lowenthal-procher20, while dry matter, organic matter, crude protein and crude fiber were quantified by proximate analysis according to AOAC21.

Experimental design: Experiments were performed in a completely randomized design using a 2×4 factorial arrangement of treatments. The first treatment variable was water temperature [fresh water (ambient temperature) or hot water (80°C)]. The second treatment factor was immersion duration (6, 12, 18 or 24 h).

Statistical analysis: Data were statistically analyzed by a two-way analysis of variance of CRD with a 2×4 factorial arrangement of treatments. Differences among treatments were determined using Duncan’s multiple range test (DMRT) according to Steel and Torrie22.

RESULTS AND DISCUSSION

Survey of waste tea leaves
Ownership of tea plantations:
The tea plantations in Indonesia were owned by the small holders, the government and a private company. "Small holders" means that the tea plantation belongs to farmers. Government plantations are owned by PTP N 6 (BUMN) and private company plantations are owned by PT. Rajawali Nusantara Indonesia (Persero/Ltd.co). Most tea plantations belong to small holders, who owned a combined area of 2,172 ha, while the government and a private company owned 604.58 and 1,470 ha, respectively.

Varieties of tea plant and tea pruning time in West Sumatra: Varieties of tea plant in the tea plantations of West Sumatra were Camellia sinensis (Assamica variety), clones TRI2024 and TRI2025. This variety (Camellia sinensis ) contains high levels of polyphenols, especially catechins23, vitamins such as A, B and C and minerals such as fluoride24 and demonstrates high leaf production25. The Assamica tea variety originated in the forests of Assam in North-Eastern India26. This variety provides the advantage of high productivity by growing quickly and producing larger leaves27. The pruning regimen for tea leaf production is every 3 years with a rotation system that depends on near-daily pruning.

Chemical composition of waste tea leaves: The following are results from the analysis of tannin content and the proximate analysis of waste tea leaves (Table 1).

Tea plantation area and waste tea leaf production: The total tea plantation area in West Sumatra was 4,246.6 ha and the total production of waste tea leaves was 25,308.28 t/year (Table 2).

The size of West Sumatera tea plantations decreases annually. In 2015, the total area of tea plantations was 4,945 ha1, while in 2017, it decreased to 4,246.6 ha. This finding is due to the conversion of tea plantations into other forms of agricultural production and settlement.

Potential of waste tea leaves as animal feed: The potential of waste tea leaves as poultry feed can be illustrated as follows: Waste tea leaf production totaled 25.25 thousand tons in fresh form, while according to Lin et al.28, fresh tea leaf moisture content is approximately 70%, meaning that when waste tea leaves are dried, their weight is approximately 17.64,000 t.

Table 1:
Tannin, dry matter, organic matter, crude fiber and crude protein content before processing of waste tea leaves
DM: Dry matter, OM: Organic matter , CF: Crude fiber, CP: Crude protein

Table 2:
Tea plantation areas and production of waste tea leaves in West Sumatra
Ha: Hectare, WTLP: Waste tea leaf production

Table 3:
Effect of water temperature and immersion duration on tannin content (%)
a,b,c,d Means with different superscripts in the same rows or columns are significantly different (p<0.05)

Table 4:
Effect of water temperature and immersion duration on dry matter content (%)
a,bMeans with different superscripts are significantly different (p<0.05)

In previous research, Krisnan29 found that fermented tea dregs of the Aspergillus niger variety could be included as up to 7.5% of the diet for laying hens. Meanwhile, Anita et al.14 reported that old tea leaves could comprise as much as 4.5% of the diet for broilers. From these findings, it is estimated that waste tea leaves could meet the dietary requirements of as many as 4,201,380,000 laying-hens/year.

Processing of waste tea leaves
Effect on tannin content:
There was an interaction (p<0.05) between water temperature and immersion duration on tannin content. Experimental results show that hot water significantly decreased (p<0.01) tannin content as shown in Table 3. Longer immersion duration also significantly decreased (p<0.01) tannin content. The interaction between water temperature and immersion duration indicated that fresh water immersion for 6 h resulted in the highest tannin content. When the duration of immersion was increased to 24 h the tannin content of waste tea leaves decreased. However, when the water temperature was increased to 80°C, tannin content declined dramatically once the immersion duration was increased to 18 h but failed to drop further when the immersion duration was increased to 24 h. Therefore, the appropriate immersion method for reducing tannin content appears to be at 80°C for 18 h. This indicates that the longer the immersion in hot water, the lower the tannin content. This decrease is due to the high solubility of tannin in water at high temperatures. According to Makkar and Becker30, high temperature is more effective at reducing tannin levels, while Rehman et al.31 performed tannin extraction on tea leaves by using water at temperatures reaching 100°C.

Effect on dry matter (DM) content: There was no interaction (p>0.05) between water temperature and duration of immersion on DM content. Water temperature also did not affect (p>0.05) the DM content of waste tea leaves. However, immersion duration significantly affected (p<0.05) DM content as seen in Table 4. The DM content at 6 and 12 h was not different (p>0.05). However, the DM content at 6 h was significantly higher (p<0.05) than at 18 and 24 h. The DM content after 12, 18 and 24 h of immersion was not significantly different (p>0.05). The highest dry matter content was at 6 and 12 h. Longer immersion times decreased DM content. This is likely because dry matter consists of organic and inorganic matter32 and organic matter contains carbohydrates that are soluble in water33,34. Martinson et al.35 reported that the dry matter content of straw decreases by as much as 11% after immersion in water for 15 min and 28% after immersion in water for 12 h. The dry matter content will decrease further with longer immersion. Decreases in dry matter content could also occur because of the loss of dissolved substances such as proteins36, vitamins37 and soluble fiber38 in water after 18 and 24 h of immersion.

Effect on organic matter (OM) content: There was no interaction (p>0.05) between water temperature and immersion duration on OM content. High water temperature significantly decreased (p<0.01) the OM content of waste tea leaves and longer immersion also significantly reduced (p<0.01) the OM content of waste tea leaves as shown in Table 5.

Table 5:
Effect of water temperature and immersion duration on organic matter content (%)
a,b,cMeans with different superscripts in the same rows or columns are significantly different (p<0.05)

Table 6:
Effect of water temperature and immersion duration on crude protein content (%)
a,bMeans with different superscripts in the same rows or columns are significantly different (p<0.05)

Table 7:
Effect of water temperature and immersion duration on crude fiber content (%)
a,bMeans with different superscripts are significantly different (p<0.05)

The OM content after hot water immersion was lower than after ambient temperature immersion. According to Paramitha39, mango flour (Mangifera indica L.) immersion in hot water (100°C) can decrease the content of organic matter by up to 3.7%. Ekarius40 defined organic matter as the dry matter of a substance that has been reduced to ash. Organic matter consists of carbohydrates, fats, proteins and vitamins. If one of these components decreases, the organic matter content also decreases.

The longer the immersion was the lower OM content of waste tea leaves. After 6 h of immersion, OM content was the highest but it was not different from levels measured after 12 h of immersion. After 18 h of immersion, the OM content was lower than after 6 and 12 h but higher than after 24 h of immersion. Therefore, immersion for 24 h resulted in the lowest OM content. Zuhro et al.41 reported that immersion of taro tuber flour for 24 h at a temperature of 80°C decreased OM content to 3.1%. The longer the immersion, the more the OM content decreased because some of the substances that contribute to OM dissolve in water. Morrison and Pirie42 reported the OM is part of the DM, so that when the DM decreases the OM will also decrease43.

Effect on crude protein (CP) content: There was no interaction (p>0.05) between water temperature and immersion duration in the crude protein content of waste tea leaves. Hot water significantly decreased (p<0.01) the CP content of waste tea leaves. Longer immersion durations also significantly decreased (p<0.01) the CP content of waste tea leaves as depicted in Table 6. The CP content of waste tea leaves immersed in hot water was significantly lower (p<0.01) than that in ambient temperature water. This result was in accordance with the results of experiments by Djafarr et al.44, who found that immersion of kerandang seeds (Canavalia virosa) in hot water (80°C) for 24 h significantly reduced crude protein content and decreased phenolic compounds by up to 74.93%. Experiments by Kajihausa et al.45 demonstrated that soaking sesame seed flour for 16 h could decrease crude protein content. Therefore, it is helpful to limit the immersion duration such that the crude protein content can be maintained. Runyons et al.36 reported that there are dissolved proteins in water-soluble foods that degrade at elevated temperatures. For example, proteins associated with albumin and prolamin are damaged by heat treatment.

Effect on crude fiber (CF) content: There was no interaction (p>0.05) between water temperature and immersion duration on the crude fiber content of waste tea leaves and immersion duration did not affect (p>0.05) the CF content of waste tea leaves. However, hot water immersion significantly increased (p<0.05) the CF content of waste tea leaves as shown in Table 7. The increase in crude fiber content of waste tea leaves was caused by a decrease in OM content. This result might be related to the study conducted by Chen et al.46, who reported that several components of food such as carbohydrates, crude protein, crude fiber, crude fat and others are lost during immersion in hot water. These losses result in increases in the crude fiber content. Waste tea leaves contain two types of fiber-soluble fiber47 and crude fiber48. Hot water immersion resulted in a decrease in soluble fiber, so the percentage of crude fiber increased. According to Cristianita et al.49, extracting soluble fiber (pectin) at a temperature of 90°C for 60 min produced a yield of 18.57%.

The results of this experiment show that immersion using hot water for a long time is more effective at reducing the tannin content of waste tea leaves. However, longer immersion times will also lower DM, OM and CP content and increase crude fiber. To maintain high levels of crude protein, our recommendation is to immerse waste tea leaves in hot water for 12 h.

CONCLUSION

The area of tea plantations in West Sumatra was 4,246.6 ha in 2017. These plantations belonged to small holders, the government and a private company and produced tea plants of the variety Camellia sinensis Assamica, Clones TRI2024 and TRI2025. The CP content of waste tea leaves was not notably high, while levels of tannin and CF content were high. The pruning time of tea leaves was every 3 years with a rotation system that involved pruning almost every day. The total production of waste tea leaves was 25,208.28 t/year, a volume with the potential to feed 4,201,380,000 laying-hens/year if included as 5% of the diet. The best processing of waste tea leaves was found to be immersion in hot water (80°C) for 12 h to reduce tannin content from 6.50-3.47% without decreasing crude protein content.

ACKNOWLEDGMENT

This study was funded by the Ministry of Research, Technology and Higher Education of the Republic of Indonesia through PMDSU No: 324/SP2H/LT/DRPM/IX/2016. We are very grateful to the Minister of Research, Technology and Higher Education of the Republic of Indonesia and the Rector of Universitas Andalas for their support.

REFERENCES
1:  Badan Pusat Statistik, 2015. Indonesia tea statistics. https://www.bps.go.id/index.php/publikasi/4262.

2:  Effendi, D.S., M. Syakir, M. Yusron and Wiratno, 2012. Cultivation and Post Harvest Tea. Badan Penelitian dan Pengembangan Pertanian, Kementerian Pertanian.

3:  Setyamidjaja, D., 2000. Tea Cultivation & Postharvesting Processing. Kementerian Pertanian, Jakarta, Indonesia.

4:  Haq, M.S. and Karyudi, 2013. Efforts to increase tea production (Camellia sinensis L. O. Kuntze) through application of technical culture. War. PPTK., 24: 71-84.

5:  Murtidjo, A.B., 1987. Guidelines for Formulating Poultry Feed. Kansius, Indonesia.

6:  Samynathan, R., S.K. Perisamy, S. Gandhi, J. Anitha, G. Sanmugam, M. Padmanabhan and G.V. Kanniappan, 2016. Biochemical and molecular analysis of Camellia sinensis (L.) O. Kuntze tea from the selected P/11/15 clone. J. Genet. Eng. Biotechnol., 14: 69-75.
CrossRef  |  Direct Link  |  

7:  Cabrera, C., R. Artacho and R. Gimenez, 2006. Beneficial effects of green tea-A review. J. Am. Coll. Nutr., 25: 79-99.
PubMed  |  Direct Link  |  

8:  Ravichandran, R., 2002. Carotenoid composition, distribution and degradation to flavour volatiles during black tea manufacture and the effect of carotenoid supplementation on tea quality and aroma. Food Chem., 78: 23-28.
CrossRef  |  Direct Link  |  

9:  Sundari, D., B. Nuratmi and M.W. Winarno, 2009. Acute toxicity of LD50 and test of green tea leaf extract (Camellia sinensis L. Kuntze) in mice. Media Litbang Kesehat, 19: 198-203.

10:  Hagerman, A.E., C.T. Robbins, Y. Weerasuriya, T.C. Wilson and C. Mcarthur, 1992. Tannin chemistry in relation to digestion. J. Range. Manage., 45: 57-62.
Direct Link  |  

11:  Wiharto, 1986. Poultry Breeding Guidelines. 2nd Edn., Universitas Brawijaya Press, Indonesia.

12:  Widodo, W., 2002. Toxic Plant in Livestock Life. Universitas Muhammadiyah Press, Indonesia.

13:  Muharlien, 2010. Improving egg quality through the addition of green tea in laying chickens feed. J. Ilmu dan Teknol. Has. Ternak, 5: 1-6.

14:  Anita, W., Y. Suharto and I. Astuti, 2012. The influence of flour tea leaf in rations on performance and abdominal fat percentage of chicken. Trop. Anim. Husb., 1: 1-6.

15:  Narsih, Yunianta and Harijono, 2008. The study on sorghum (Sorghum bicolor L. Moench) soaking and germination time to produce low tannin and phytic acid flour. J. Teknologi Pertanian, 9: 173-180.
Direct Link  |  

16:  Kawamoto, H., F. Nakatsubo and K. Murakami, 1990. Synthesis of condensed tannin derivatives and their protein-precipitating capacity. J. Wood Chem. Technol., 10: 59-74.
CrossRef  |  Direct Link  |  

17:  Goodarznia, I. and A.A. Govar, 2009. Superheated water extraction of catechins from green tea leaves: Modeling and simulation. Trans. C: Chem. Chem. Eng., 16: 99-107.
Direct Link  |  

18:  Oematan, Z.Z.B., 2015. Effect of temperature difference and time of extraction on tannin content of cashew leaf extract. J. Ilm. Mhs. Univ. Surabaya, 4: 1-12.

19:  Subandriyo and N.I. Setianingsih, 2016. Extraction process for reducing tannin of mangrove fruit [Bruguiera gumnorrhiza (Lamarck, 1798)] as a raw material for food flour. Aquat. Procedia, 7: 231-235.
CrossRef  |  Direct Link  |  

20:  Sudarmadji, S., H. Bambang and Suhardi, 1984. Procedure Analysis for Food and Agriculture. Liberty Yogyakart, Indonesia, pp: 108.

21:  AOAC., 1990. Official Method of Analysis. 15th Edn., Association of Official Analytical Chemists, Washington, DC., USA., pp: 66-88.

22:  Steel, R.G.D. and J.H. Torrie, 1990. Principles and Procedure of Statistics: A Biometrical Approach. McGraw Hill Book Co. Inc., USA.

23:  Sriyadi, B., 2012. Selection of superior assamica tea clones with high yield potential and high catechine contents. J. Penelitian Teh dan Kina, 15: 1-10.
Direct Link  |  

24:  Lu, Y., W.F. Guo and X.Q. Yang, 2004. Fluoride content in tea and its relationship with tea quality. J. Agric. Food Chem., 52: 4472-4476.
CrossRef  |  Direct Link  |  

25:  Kamau, D.M., 2008. Productivity and Resource use in Ageing Tea Plantations. Wageningen University, The Netherlands, Pages: 140.

26:  Van der Vossen, H.A.M. and M. Wessel, 2000. PROSEA: Plant Resources of South-East Asia No. 16: Stimulants. Backhuys Publishers, Leiden, The Netherlands, pp: 55-63.

27:  Kalita, R.M., A.K. Das and A.J. Nath, 2014. Comparative study on growth performance of two shade trees in tea agroforestry system. J. Environ. Biol., 35: 699-702.
Direct Link  |  

28:  Lin, X., L. Zhang, H. Lei, H. Zhang, Y. Cheng, R. Zhu and R. Ruan, 2010. Effect of drying technologies on quality of green tea. Int. Agric. Engin. J., 19: 30-37.
Direct Link  |  

29:  Krisnan, R., 2005. The Effect of feeding tea shake (Camellia sinensis) fermentation with Aspergillus niger in broiler chickens. JITV., 10: 1-5.

30:  Makkar, H.P.S. and K. Becker, 1996. Effect of pH, temperature and time on inactivation of tannins and possible implications in detannification studies. J. Agric. Food Chem., 44: 1291-1295.
CrossRef  |  Direct Link  |  

31:  Rehman, S.U., K. Almas, N. Shahzadi, N. Bhatti and A. Saleem, 2002. Effect of time and temperature on infusion of tannins from commercial brands of tea. Int. J. Agric. Biol., 4: 285-287.
Direct Link  |  

32:  Oetzel, G.R., F.P. Villalba, W.J. Goodger and K.V. Nordlund, 1993. A comparison of on-farm methods for estimating the dry matter content of feed ingredients. J. Dairy Sci., 76: 293-299.
CrossRef  |  Direct Link  |  

33:  Chalbot, M.C.G., P. Chitranshi, G.G. da Costa, E. Pollock and I.G. Kavouras, 2016. Characterization of water-soluble organic matter in urban aerosol by 1H-NMR spectroscopy. Atmos. Environ., 128: 235-245.
CrossRef  |  Direct Link  |  

34:  Martinson, K., H. Jung, M. Hathaway and C. Sheaffer, 2012. The effect of soaking on carbohydrate removal and dry matter loss in orchardgrass and alfalfa hays. J. Equine Vet. Sci., 32: 332-338.
CrossRef  |  Direct Link  |  

35:  Martinson, K., M. Hathaway, H. Jung and C. Sheaffer, 2017. Hay soaking: All washed up or a good management option? https://www.extension.umn.edu/agriculture/horse/nutrition/hay-soaking/.

36:  Runyon, J.R., B.A. Sunilkumar, L. Nilsson, A. Rascon and B. Bergenstahl, 2015. The effect of heat treatment on the soluble protein content of oats. J. Cereal Sci., 65: 119-124.
CrossRef  |  Direct Link  |  

37:  Sami, R., Y. Li, B. Qi, S. Wang and Q. Zhang et al., 2014. HPLC analysis of water-soluble vitamins (B2, B3, B6, B12 and C) and fat-soluble vitamins (E, K, D, A and β-carotene) of Okra (Abelmoschus esculentus). J. Chem. 10.1155/2014/831357

38:  Yan, X., R. Ye and Y. Chen, 2015. Blasting extrusion processing: The increase of soluble dietary fiber content and extraction of soluble-fiber polysaccharides from wheat bran. Food Chem., 180: 106-115.
CrossRef  |  Direct Link  |  

39:  Paramita, O., 2013. Effect of water tender type on vitamin C, fiber and mango flour protein (Mangifera indica L.). J. Bahan Alam, 2: 24-30.

40:  Ekarius, C., 2015. The Essential Guide to Hobby Farming: The How-To Manual for Creating a Hobby Farm. i5 Publishing, USA., ISBN: 9781620081440, Pages: 304.

41:  Zuhro, M., M. Lutfi and L. C. Hawa, 2015. The influence of immersion time and drying temperature on psychochemical characteristic of taro tuber flour (Xanthosoma sagittifolium). J. Bioproses Komod. Trop., 3: 26-32.

42:  Morrison, J.E. and N.W. Pirie, 1961. The large-scale production of protein from leaf extracts. J. Sci. Food Agric., 12: 1-5.
CrossRef  |  Direct Link  |  

43:  Bautrif, E., 1990. Recent Development in Quality Evaluation. Food Policy and Nutrion Division, FAO., Rome.

44:  Djaafar, T.F., U. Santosa, M.N. Cahyanto and E.S. Rahayu, 2012. The effect of soaking and boiling on protein, oligosaccharides, total phenolic content and antioxidant activity of kerandang (Canavalia virosa). Agritech, 32: 294-300.
Direct Link  |  

45:  Kajihausa, O.E., R.A. Fasasi and Y.M. Atolagbe, 2014. Effect of different soaking time and boiling on the proximate composition and functional properties of sprouted sesame seed flour. Niger. Food J., 32: 8-15.
CrossRef  |  Direct Link  |  

46:  Chen, Y., R. McGee, G. Vandemark, M. Brick and H.J. Thompson, 2016. Dietary fiber analysis of four pulses using AOAC 2011.25: Implications for human health. Nutrients, Vol. 8, No. 12. 10.3390/nu8120829

47:  Ele-Ekouna, J.P., C. Pau-Roblot, B. Courtois and J. Courtois, 2011. Chemical characterization of pectin from green tea (Camellia sinensis). Carbohydr. Polym., 83: 1232-1239.
CrossRef  |  Direct Link  |  

48:  Guo, W., Y. Shu and X. Yang, 2016. Tea dietary fiber improves serum and hepatic lipid profiles in mice fed a high cholesterol diet. Plant Foods Hum. Nutr., 71: 145-150.
CrossRef  |  Direct Link  |  

49:  Christianita, A.A.M., S.B. Widjanarko and I.M. Purwantiningrum, 2014. Colored pectin production using apple pomace and red rose filtrate addition. J. Pangan dan Agroindustri, 2: 159-169.
Direct Link  |  

©  2020 Science Alert. All Rights Reserved