This document discusses methods for extracting protein from rice bran, including a two-step enzymatic hydrolysis method. The two-step method uses alkaline protease and glucoamylase to extract 62.8% of the protein from rice bran meal. Thermally stable rice bran meal and low-temperature leached rice bran meal produce proteins with similar functionality, though thermally stable rice bran yields less. A double enzymatic method using neutral and alkaline proteases produces rice bran polypeptides. While this research increases the extracted protein content to 90%, further study of peptide biological activity and food industry applications is still needed.

1. Rice Bran Protein and Polypeptide
Development by Complex
Enzymatic Hydrolysis
Lifeng Zhou
Oils and Fats Sub-association of Chinese Cereals and Oils Association
May 25th,2018

2. OUTLINE
• Background
• Preparation of Rice Bran Protein by Two-step enzyme treatment
• Comparative Study on the Preparation of Rice Bran Protein by
Thermally Stable Rice Bran Meal and Low-temperature Leaching Rice
Bran Meal
• Preparation and Functional Evaluation of Rice Bran Polypeptides by
Double Enzymatic Method
• Summary

3. Rice Bran Protein
• Rice bran is a low-cost but nutritious rice processing by-product，a renewable
resource.
• Rice bran protein is a well-recognized high-quality vegetable protein.
• Its essential amino acid composition balance is reasonable and it is close to the
FAO/WHO recommendation model.
• The content of protein in defatted rice bran can be as high as 18%.
• Rice bran protein is a hypoallergenic protein that does not produce allergic
reactions and is suitable for infants and special people.
Background

4. Rice bran protein preparation methods
Methods
Alkali dissolution and
acid precipitation
Enzymatic method
Physical extraction
Background

5. • Fresh rice bran is not easy to store, and the thermally stable rice bran
meal has become another important form of rice bran resources.
• Due to the high degree of protein denaturation in rice bran, the extracted
rice bran protein has poor water solubility, poor functional properties, and
low protein content, making it difficult to be a good food material.
• Using Thermally Stable Rice Bran Meal as a raw material to obtain small
peptides that are beneficial for absorption.
Background

6. OUTLINE
• Background
• Preparation of Rice Bran Protein by Two-step enzyme treatment
• Comparative Study on the Preparation of Rice Bran Protein by
Thermally Stable Rice Bran Meal and Low-temperature Leaching
Rice Bran Meal
• Preparation and Functional Evaluation of Rice Bran Polypeptides by
Double Enzymatic Method
• Summary

7. • In this study, the enzymatic
method, the alkali-soluble
acid precipitation method,
and the ultrasound-assisted
method were organically
combined to prevent growth
and avoid side-effects
caused by over-alkalization.
Preparation of Rice Bran Protein by Two-step enzyme treatment
Rice bran
meal
Disperse with
deionized
water
Adjust pH
Adjust
temperature
Add Alkaline
protease
Inactivating
enzyme
Alkaline
extraction
Ultrasonic
extraction
Centrifugal
filter Adjust pH
Resting
Centrifugal
Dissolved
Precipitate
Adjust pH
Freeze-drying
Rice bran
protein

10. • The Extraction ratio of protein is 62.8%.
• Through verification, they are the best experimental conditions.
Preparation of Rice Bran Protein by Two-step enzyme treatment
The primary and secondary order
1. Extraction temperature
2. Extraction time
3. pH
4. Solid-Liquid ratio
5. Ultrasonic power
Extraction temperature 50℃
pH 10.5
Extraction time 100 min
Solid-Liquid ratio 1:10
ultrasonic power 220 W

11. Meal protein
Dissolved
with deionized
water
Adjust pH
Adjust
temperature
Add
Glucoamylase
Inactivating
enzyme
separate Freeze-drying Product
Preparation of Rice Bran Protein by Two-step enzyme treatment

13. • The protein yield was as high as 82.43%.
The primary and secondary order
1. Extraction temperature
2. pH
3. Extraction time
4. Liquid-Solid ratio
5. Enzyme dosage
Extraction temperature 60℃
pH 4.5
Extraction time 1.5h
Liquid-Solid ratio 3:1
Enzyme dosage 0.3%

14. Relationship between glucoamylase treatment
times and product protein content
• The content of protein after treatment
with glucoamylase increased a lot, but
the extraction ratio decreased.
• This is because the content of sugar in
the protein is removed, resulting in an
increase in protein purity and a
decrease in the extraction rate.
Considering the cost of production, rice bran protein should be
subjected to two enzymatic treatments to make the protein content 90%.

15. OUTLINE
• Background
• Preparation of Rice Bran Protein by Two-step enzyme treatment
• Comparative Study on the Preparation of Rice Bran Protein by
Thermally Stable Rice Bran Meal and Low-temperature Leaching
Rice Bran Meal
• Preparation and Functional Evaluation of Rice Bran Polypeptides by
Double Enzymatic Method
• Summary

16. Thermally stable r ice bran
meal is a product that has
been subjected to high-
temperature treatment during
the production of rice bran oil
from rice bran.
Relatively low solubility limits
the use of proteins in thermally
stable rice bran in foods.

17. • The functionality of the two
proteins is similar. If we ignore
higher yields, thermally stable rice
bran protein can still be added to
foods as a better quality protein.

18. OUTLINE
• Background
• Preparation of Rice Bran Protein by Two-step enzyme treatment
• Comparative Study on the Preparation of Rice Bran Protein by
Thermally Stable Rice Bran Meal and Low-temperature Leaching
Rice Bran Meal
• Preparation and Functional Evaluation of Rice Bran Polypeptides by
Double Enzymatic Method
• Summary

19. Preparation and Functional Evaluation of Rice Bran Polypeptides by
Double Enzymatic Method
Rice bran
protein
AdjustpH
Add
neutral
protease
Inactivating
enzyme
Centrifugal
Adjust pH of
Supernatant
Add
alkaline
protease
Inactivating
enzyme
Centrifugal
Desalination
treatment of
supernatant
Concentrate Freeze-drying
Rice Bran
Polypeptides

21. • Rice bran protein peptide was prepared by enzymatic hydrolysis of rice bran
protein with alkaline protease. It has the advantages of high hydrolysis, high
yield and low price.
• Little difference between the products prepared from two kinds of rice bran meal.
Preparation and Functional Evaluation of Rice Bran Polypeptides by
Double Enzymatic Method

22. OUTLINE
• Background
• Preparation of Rice Bran Protein by Two-step enzyme treatment
• Comparative Study on the Preparation of Rice Bran Protein by
Thermally Stable Rice Bran Meal and Low-temperature Leaching
Rice Bran Meal
• Preparation and Functional Evaluation of Rice Bran Polypeptides by
Double Enzymatic Method
• Summary

23. • Increased protein production to 90% with two glucoamylase
treatments.
• If ignore higher yields, thermally stable rice bran protein can still
be added to foods as a better quality protein.
• However, the biological activity of rice bran protein peptides needs
to be further studied, and its application in the food industry needs
to be further developed.
Summary

24. Thank you for the attention!