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What Is DOBI (Deterioration of Bleachability Index)? Definition, Measurement, and Its Impact

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Byadmin01
🕑 11 Nov 2026⏱ 9 min read1,655 words
Key Points
  • DOBI is the ratio of absorbance at 446 nm (carotene) to 269 nm (secondary oxidation products), which guides how easily crude palm oil (CPO) can be bleached.
  • SNI 2901:2021 sets a minimum DOBI of 2.0 for regular CPO; the premium class has a tighter limit.
  • CPO with a DOBI below 2.5 tends to produce refined oil with a higher colour value.
  • DOBI is affected by fruit maturity, processing delays and temperature, blending with recycled oil, and oxidation during transport and storage.
  • DOBI is measured by UV-Vis spectrophotometry, referring to the PORIM/MPOB P2.9 method.

DOBI is a CPO quality parameter used by mills and buyers to judge how easily the oil can be bleached during refining. A high value means carotene is still abundant and oxidation products are few; a low value indicates the oil has oxidised further.

What Is DOBI?

DOBI stands for Deterioration of Bleachability Index, an index of the loss of bleachability. This index serves as a guide to assess how easily a CPO sample can be bleached. Its value is obtained from the ratio of absorbance at 446 nm, which represents the carotene content, to absorbance at 269 nm, which represents secondary oxidation products.[1]

The higher the DOBI, the more carotene and the fewer oxidation products in the oil. As a mill benchmark, a DOBI above 3 is considered good quality, while average quality is above 2.3.[2]

DOBI is not a substitute for FFA. FFA forms through hydrolysis caused by water, heat, and the enzyme lipase, while DOBI reflects carotene and secondary oxidation products. DOBI therefore needs to be read together with other parameters. Mills have encountered CPO with high FFA, a DOBI above 2.5, and a low peroxide value (PV) that still produced refined oil with a high colour value.[1]

How Is DOBI Measured?

DOBI is determined by UV-Vis spectrophotometry. A CPO sample is dissolved in an organic solvent such as isooctane, and its absorbance is read at 446 nm and 269 nm. Palm oil research laboratories in Indonesia use the PORIM P2.9 method for DOBI analysis.[3]

The DOBI value is calculated as follows:[4]

DOBI = Absorbance at 446 nm ÷ Absorbance at 269 nm

DOBI Quality Standards for CPO

In Indonesia, DOBI is set as a CPO quality parameter in SNI 2901:2021. This standard distinguishes premium and regular CPO classes. For the regular class, the maximum FFA is 5.0% and the minimum DOBI is 2.0. The premium class has tighter limits, for example a moisture content below 0.25%. The full premium class limits can be seen directly in the SNI document.[5]

Table 1. DOBI limits in SNI and several comparison specifications
Standard or specification Class Max. FFA Min. DOBI
SNI 2901:2021 Regular CPO 5.0% 2.0
PORAM/MPOA, Malaysian domestic sales contract Trade specification 5.0% 2.3 at loading; 2.1 to below 2.3 with adjustment; below 2.1 rejected
MS 814 (Malaysia) Special Quality 2.5% 2.8
MS 814 (Malaysia) Standard Quality 5.0% 2.3
CPO receiving control at a Malaysian mill Internal target below 4.0% above 2.5
Source: Safwa (2026) for the SNI 2901:2021 regular class; Ng (2018) for PORAM/MPOA specifications, MS 814, and mill receiving control. The premium class limits of SNI 2901:2021 refer to the SNI document.

A 2025 study by the Indonesian Oil Palm Research Center (PPKS) noted that many palm oil mills have not fully aligned themselves with SNI 2901:2021, which includes DOBI as a parameter. Sales contracts still often refer to specifications similar to the old SNI (2006) that focus on FFA (maximum 5%) and moisture and impurities (maximum 0.50%), without including DOBI. Some mills only analyse DOBI on special request for premium CPO contracts.[6]

Factors That Lower DOBI

Fruit maturity. Processing a large amount of unripe fruit is among the main causes of low DOBI. The link is through carotene: carotene content correlates strongly and positively with DOBI, so when carotene degrades, the DOBI value falls as well.[6]

Processing at the mill. Mill practitioners note causes of low DOBI including processing delays, overlong sterilisation, CPO contaminated by steriliser condensate water, and mixing with oil from the sludge pond that has already oxidised severely. A PPKS study recorded that DOBI tends to fall up to the screw press stage due to sterilisation heat and stirring that damage carotenoids. The value rises at the clarification stage (clarification tank and oil tank) because oxidised carotenoids are removed with the sludge, then falls again in the vacuum dryer and storage tanks. A sharp decline occurs in mills without their own estates that blend main CPO with low-quality recycled oil from the sludge pond.[6]

Storage and transport. Heating CPO in tanks above 55°C is among the causes of low DOBI, and a storage temperature of 45–55°C is recommended to suppress the rise in PV and FFA.[6] After leaving the mill, oxidation continues during transport and storage due to oxygen exposure, temperature fluctuations, and contact with catalytic surfaces.[7]

Metals. Metal content such as iron and copper is among the factors that affect CPO quality, alongside moisture, FFA, and impurities.[8]

The Effect of DOBI on Refining and Cost

DOBI helps estimate how easily CPO can be bleached. According to mill practitioners, CPO with a DOBI below 2.5 tends to produce refined oil with a higher colour value.[1] Besides DOBI, high FFA and high PV also demand a larger bleaching earth dose. High PV even adds oil loss through spent bleaching earth and raises process cost.[1]

Quality requirements differ between downstream industries. The refining (oleofood) and oleochemical industries require CPO with good oxidative stability (high DOBI) and low FFA, while the biodiesel industry is far more tolerant.[7]

A study of bleaching CPO with different DOBI values showed that raising the time and dose of bleaching earth reduces the colour, carotene, DOBI, and moisture content of the bleached oil.[9] The DOBI decrease here occurs in the oil after bleaching because carotene is also reduced, so it does not mean the original CPO quality was worse.

There is an important note about blending. Blending low-quality CPO into high-quality CPO lowers carotene and DOBI, while FFA and PV rise.[9] A blend whose DOBI appears high can still have increased FFA, and this affects the subsequent deodorisation process.[9] For this reason, efforts to “chase” a DOBI number through blending affect other quality parameters.

DOBI in Field Data

Field data shows that Indonesian CPO DOBI varies widely and tends to fall along the supply chain. A survey of 34 palm oil mills in Sumatra, Kalimantan, and Sulawesi (2019–2020) recorded an average DOBI of 2.42 with a range of 1.26–3.10.[10]

Table 2. DOBI values from various field sources
Source DOBI Note
Survey of 34 mills in Sumatra, Kalimantan, and Sulawesi (2019–2020) 2.42 ± 0.42 (range 1.26–3.10) Lowest value below the SNI 2901:2021 regular limit (2.0)
CPO dispatched from two supplier mills of a refinery (PPKS case study) 2.65–2.87 Measured when dispatched from the mill
CPO arriving at the refinery, monthly average 2024 (PPKS case study) 2.21–2.35 Truck 2.21–2.28; pipeline 2.21–2.35
CPO in the refinery feed tank (one sample, PPKS case study) 2.19 After storage at the refinery
CPO at the dispatch unit of a mill (D3 final project, Universitas Jambi) 2.002–2.150 One sample approaching the lower SNI 2901:2021 limit
Source: Andarwulan et al. (IPB University), Siahaan et al. (2025), and Safwa (2026). The figures come from different studies and laboratories so they cannot be compared directly.

An important finding from the supply chain case study: the DOBI of CPO dispatched from two supplier mills ranged from 2.65 to 2.87, but after arriving and being stored at the refinery it fell to around 2.2–2.35. That decline indicates oxidation during transport and storage.[7] It should be noted that this is a case study at one refinery. During short-term storage at that refinery itself, DOBI was relatively stable (2.18 to 2.19), but PV rose from 0.75 to 2.13.[7]

Summary

DOBI is an index of the loss of bleachability of CPO, calculated from the ratio of absorbance at 446 nm to 269 nm. A high value indicates high carotene and low oxidation, so the oil is easier to bleach. SNI 2901:2021 sets a minimum DOBI of 2.0 for regular CPO and a tighter limit for the premium class. Keeping DOBI high means processing ripe fruit without delay, avoiding excessive heating and blending with poor recycled oil, and minimising oxidation during transport and storage.

References

  1. Ng, S. K. (2018). Refinery Crude Palm Oil Quality. MOSTA Best Practices Workshop, 14–15 August 2018. Palmaju Edible Oil Sdn. Bhd. https://mosta.org.my/wp-content/uploads/2018/08/1.3-Ng-Siew-Kwan.pdf
  2. Malaysian Palm Oil Board (MPOB). MPOB Test Method P2.9 — Determination of Deterioration of Bleachability Index (DOBI) in Palm Oil.
  3. Malaysian Palm Oil Board (MPOB). MPOB Technical — TT No. 253: DOBI. https://tot.mpob.gov.my/wp-content/uploads/2020/02/TT-253.pdf
  4. Universitas Sumatera Utara. Penentuan Dobi (Deterioration of Bleachability Index) dalam Crude Palm Oil (CPO). https://repositori.usu.ac.id/bitstream/handle/123456789/49879/192401071.pdf
  5. Badan Standardisasi Nasional (BSN). SNI 2901:2021: Minyak Kelapa Sawit Mentah (Crude Palm Oil). BSN, Jakarta. https://pesta.bsn.go.id/produk/detail/13323-sni29012021
  6. Safwa, A. (2026). Analisis Asam Lemak Bebas, Kadar Air, dan Deterioration of Bleachability Index (DOBI) sebagai Parameter Mutu Crude Palm Oil. Tugas akhir D3, Universitas Jambi. https://repository.unja.ac.id/105048/
  7. Siahaan, D., Rizki, I. F., Panjaitan, F. R., Mulyono, M. E., Bajra, B. D., & Salendra, M. (2025). Factors affecting crude palm oil quality across the supply chain and implications for downstream industries in North Sumatra and Riau. Menara Perkebunan, 93(2), 93–105. https://mp.iribb.org/index.php/mpjurnal/article/download/646/519
  8. Lengke, G., et al. (2024). Evaluasi Kualitas Minyak Sawit Mentah (CPO) PT Suryaraya Lestari I. Pharmaceutical and Cosmetic Journal, 2(1), Universitas Kristen Indonesia Paulus. https://ojs.ukipaulus.ac.id/index.php/pcj/article/download/621/581
  9. Pengaruh Dosis Bleaching Earth dan Waktu Pemucatan Crude Palm Oil yang Bervariasi Deterioration of Bleachability Index (DOBI) terhadap Mutu Produk. Jurnal Teknologi Industri Pertanian, IPB University. https://journal.ipb.ac.id/index.php/jurnaltin/article/view/17106
  10. Andarwulan, N., Hariyadi, P., Giriwono, P. E., & Faridah, D. N. Standar Mutu CPO untuk Minyak Makan dan Penerapan Cara Produksi Minyak Sawit yang Baik di Indonesia: Suatu Keniscayaan. Policy brief, Agro-Maritim, IPB University. https://jai.ipb.ac.id/index.php/agro-maritim/article/download/53653/27507
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