Are lentils and rice a complete protein?
By
Dr Jorge Metri (PhD)
| Reviewed by
Dr Anny Manrich (PhD)
The contents of this article are fact-based except otherwise stated within the article.
Author bio
Dr Jorge Metri PhD is a Nutritionist with vast experience in food design with natural ingredients. He also researches sensory sciences and food quality with cutting-edge technologies like Machine Learning. He writes and reviews content on these topics.
Dr Jorge Metri’s highlights:
- Invited Reviewer of two international scientific Journals
- PhD in Food Science with emphasis on reduced-fat salad dressings with non-animal derived proteins at Universidad De Las Américas Puebla
- Diploma in Artificial Intelligence at Universidad Anáhuac, México
- Bachelor’s degree in Nutrition at the Universidad Latino
“Science shows its true impact when we make it understandable for everyone” – Dr Jorge Metri PhD.
Professional experience:
Prior to doing his PhD, Jorge Metri worked as an independent nutritionist for almost two years, focusing on sports nutrition to enhance the performance of swimmers and triathletes.
Jorge Metri has worked on several multidisciplinary research projects, including fruit processing, the production of protein-based products, spices, seasonings, jams, and artificial intelligence applied to agriculture production and food quality.
In the food technology area, Jorge Metri has contributed to improving sales and profits of two entrepreneurs of artisanal food products by reformulating their products and standardizing their processes.
Due to the high volume of food production and innovation, the food industry will need new technologies for food characterization in the next years; Jorge Metri is looking for studying such technologies, in 2022, he was selected as a finalist in the IFT FIRST 2022 Food Science event for the Sensory & Consumer Sciences Division Graduate Student Pangborn Oral Competition with the work titled: Machine Learning Models for Mayonnaise Acceptability Prediction.
Education:
- 2018 – 2023: PhD in Food Science at Universidad De Las Américas Puebla of Puebla, México
- 2022: Diploma in Artificial Intelligence at Universidad Anáhuac, México
- 2011 – 2016: Bachelor’s degree in Nutrition at the Universidad Latino of Mérida Yucatán, México.
Main publications of Jorge Metri:
- Metri-Ojeda, J., Solana-Lavalle, G., Rosas-Romero, R., Palou, E., & Baigts-Allende, D. (2023). Rapid screening of mayonnaise quality using computer vision and machine learning. Journal of Food Measurement and Characterization, 1-13.
- Metri-Ojeda, J., Ramírez-Rodrigues, M., Rosas-Ordoñez, L., & Baigts-Allende, D. (2022). Development and Characterization of a Low-Fat Mayonnaise Salad Dressing Based on Arthrospira platensis Protein Concentrate and Sodium Alginate. Applied Sciences, 12(15), 7456.
- Ojeda, J. M., Rodrigues, M. R., & Allende, D. B. (2022). Study of the perception and the acceptability of mayonnaise ingredients among Mexican consumers and its global preference. Revista Española de Nutrición Humana y Dietética, 26.
- Metri-Ojeda, J., Nikiforidis, C., Sandoval-Peraza, M., Chel-Guerrero, L., & Baigts, D. (2019). Processing of Amaranthus hypochondriacus biomass for functional protein concentrates development. Journal of Food Research, 8(5), 70-81.
Conference papers:
- Allende, D. B., Alva, A. P., Haro, M. S., Martínez, A. S., & Ojeda, J. M. (2020). Bio-plastic polymers from renewable sources. INNOTEC, (19 ene-jun), 97-108
- Metri-Ojeda, J. C., Pérez-Alva, A., Recio-Cazares, S. L., & Baigts-Allende, D. K. (2020). Physicochemical and sensorial characterization of vegan mayonnaise using chia seed oil and mucilage (Salvia hipanica L.). Investigación y Desarrollo en Ciencia y Tecnología de Alimentos, 5, 485-489.
You can view some of Dr Metri’s work below and links to his professional profiles:
LinkedIn: https://www.linkedin.com/in/jorge-metri-ojeda/
Research Gate: https://www.researchgate.net/profile/Jorge-Carlos-Metri-Ojeda-2
Google Scholar: https://scholar.google.com/citations?user=SBi5hE8AAAAJ&hl=es
ORCID: https://orcid.org/0000-0002-7333-3688
Reviewer bio
Dr Anny Manrich PhD is a food Engineer with expertise in Food Technology, Natural Polymers, Edible Films, Enzymes, and Nanotechnology. She writes and reviews content on these topics.
Dr Anny Manrich’s Highlights:
- Research and Technology at the Brazilian Agricultural Research Corporation
- PhD in Chemical Engineering with a focus on Biochemistry at the Federal University of Sao Carlos/ Brazil and a one-year scholarship at the Technical University of Munich/ Germany
- Bachelor of Food Engineering at the University of Campinas/ Brazil and a one-year scholarship at the Technical University of Munich/ Germany
“To solve a problem, global vision and multifactorial understanding are necessary. Therefore, in addition to expertise, one should seek multidisciplinary thinking connected with science and reality” – Dr Anny Manrich, PhD.
Professional Experience:
Dr Anny Manrich’s Experience Joining the Brazilian Agricultural Research Corporation, as soon as she completed her doctorate,
Dr Anny Manrich has worked on several projects, including the more than three-year partnership project with BRF, a major food producer in Brazil. As a postdoctoral fellow.
Dr Anny Manrich has also contributed to several business consultancies and research projects of the National Nanotechnology Laboratory System in areas such as food technology, fibres, films and coatings and Nanotechnology; in a very determined way, having a great team relationship, being creative and committed.
Growing concerns about the safe introduction of nanomaterials into today’s life emphasises the need to create regulatory documentation in front of characterising, using and testing them. Dr Anny Manrich worked for two years on a characterization project for nanoscale materials, with the aim of exploring their possible health effects.
Despite not having specific academic training in packaging or polymeric films, Dr Anny Manrich works at the Brazilian Agricultural Research Corporation in areas of edible and biodegradable films produced from agricultural waste and in the development of films with greater resistance to water, having articles published in renowned scientific journals, which demonstrates her multidisciplinary understanding and creativity.
In addition, she worked for four years as a consultant to a food company to develop a line of snacks that are healthy and that add functional ingredients, physiologically active compounds that bring health benefits, made from fruits and vegetables, enabling diet improvement, disease prevention and reduction of nutritional deficiencies.
Dr Anny Manrich participated as a member of the examination board for two Master’s exams and one PhD exam at the Department of Chemical Engineering of the Federal University of São Carlos.
Education:
- 2001 Bachelor in Food Engineering at the State University of Campinas, Brazil
- 1999 One year scholarship at the Technical University of Munich
- 2004 Master in Chemical Engineering at the Federal University of São Carlos, Brazil
- 2012 PhD in Chemical Engineering at the Federal University of São Carlos, Brazil
- 2010 One year scholarship at the Technical University of Munich
The main publications of Dr. Anny Manrich are:
Articles
Manrich, A., Moreira, F. K., Otoni, C. G., Lorevice, M. V., Martins, M. A., & Mattoso, L. H. (2017). Hydrophobic edible films made up of tomato cutin and pectin. Carbohydrate Polymers, 164, 83-91.
Mendes, J. F., Norcino, L. B., Martins, H. H. A., Manrich, A., Otoni, C. G., Carvalho, E. E. N., … & Mattoso, L. H. C. (2020). Correlating emulsion characteristics with the properties of active starch films loaded with lemongrass essential oil. Food Hydrocolloids, 100, 105428.
Norcino, L. B., Mendes, J. F., Natarelli, C. V. L., Manrich, A., Oliveira, J. E., & Mattoso, L. H. C. (2020). Pectin films loaded with copaiba oil nanoemulsions for potential use as bio-based active packaging. Food Hydrocolloids, 106, 105862.
Manrich, Anny, et al. Immobilization of trypsin on chitosan gels: Use of different activation protocols and comparison with other supports. International Journal of Biological Macromolecules 43.1 (2008): 54-61.
Manrich, Anny; Komesu, Andrea ; Adriano, Wellington Sabino; Tardioli, Paulo Waldir ; Giordano, Raquel Lima Camargo . Immobilization and Stabilization of Xylanase by Multipoint Covalent Attachment on Agarose and on Chitosan Supports. Applied Biochemistry and Biotechnology, v. 161, p. 455-467, 2010.
Mendes, J. F., Martins, J. T., Manrich, A., Neto, A. S., Pinheiro, A. C. M., Mattoso, L. H. C., & Martins, M. A. (2019). Development and physical-chemical properties of pectin film reinforced with spent coffee grounds by continuous casting. Carbohydrate polymers, 210, 92-99..
Milessi, T. S., Kopp, W., Rojas, M. J., Manrich, A., Baptista-Neto, A., Tardioli, P. W., … & Giordano, R. L. (2016). Immobilization and stabilization of an endoxylanase from Bacillus subtilis (XynA) for xylooligosaccharides (XOs) production. Catalysis Today, 259, 130-139.
Mendes, J. F., Norcino, L. B., Manrich, A., Pinheiro, A. C. M., Oliveira, J. E., & Mattoso, L. H. C. (2020). Development, physical‐chemical properties, and photodegradation of pectin film reinforced with malt bagasse fibers by continuous casting. Journal of Applied Polymer Science, 137(39), 49178.
Mendes, J. F., Martins, J. T., Manrich, A., Luchesi, B. R., Dantas, A. P. S., Vanderlei, R. M., … & Martins, M. A. (2021). Thermo-physical and mechanical characteristics of composites based on high-density polyethylene (HDPE) e spent coffee grounds (SCG). Journal of Polymers and the Environment, 29, 2888-2900..
Mendes, J. F., Norcino, L. B., Martins, H. H., Manrich, A., Otoni, C. G., Carvalho, E. E. N., … & Mattoso, L. H. C. (2021). Development of quaternary nanocomposites made up of cassava starch, cocoa butter, lemongrass essential oil nanoemulsion, and brewery spent grain fibers. Journal of Food Science, 86(5), 1979-1996.
Manrich, A., Martins, M. A., & Mattoso, L. H. C. (2021). Manufacture and performance of peanut skin cellulose nanocrystals. Scientia Agricola, 79.
Nascimento, V. M., Manrich, A., Tardioli, P. W., de Campos Giordano, R., de Moraes Rocha, G. J., & Giordano, R. D. L. C. (2016). Alkaline pretreatment for practicable production of ethanol and xylooligosaccharides. Bioethanol, 2(1)..
Manrich, Anny, de Oliveira, J. E., Martins, M. A., & Mattoso, L. H. C. Physicochemical and Thermal Characterization of the Spirulina platensis. J. Agric. Sci. Technol. B, v. 10, p. 298-307, 2020.
Book Chapter
Terra, I. A. A., Aoki, P. H., Delezuk, J. A. D. M., Martins, M. A., Manrich, A., Silva, M. J., … & Miranda, P. B. (2022). Técnicas de Caracterização de Polímeros. Nanotecnologia Aplicada a Polímeros, 614.
Conference Papers
Ferreira, L. F., Luvizaro, L. B., Manrich, A., Martins, M. A., Júnior, M. G., & Dias, M. V. (2017). Comparação da estabilidade de suspensões poliméricas de amido/tocoferol e quitosana/tocoferol. In: CONGRESSO BRASILEIRO DE POLÍMEROS, 14., 2017, Águas de Lindóia, SP.
Manrich, A., Hubinger, S. Z., & Paris, E. C. (2017). Citotoxicidade causada por nanomateriais: avaliação do micronúcleo. In: WORKSHOP DA REDE DE NANOTECNOLOGIA APLICADA AO AGRONEGÓCIO, 9., 2017, São Carlos. Anais… São Carlos: Embrapa Instrumentação, 2017. p. 655-658.
Manrich, Anny, et al. Immobilization and Stabilization of Xylanase by multipoint covalent attachment on Glyoxyl Agarose Support. The 31st Symposium on Biotechnology for Fuels and Chemicals. 2009.
Manrich, Anny, et al. Application of immobilized xylanase on hydrolysis of soluble wood hemicelluloses after using microwave and organosolv pre-treatments. The 32nd Symposium on Biotechnology for Fuels and Chemicals. 2010.
You can view some of Dr Anny’s work below and links to her professional profile.
Research Gate: https://www.researchgate.net/profile/Anny-Manrich-2
Scopus: https://www.scopus.com/authid/detail.uri?authorId=23103497100
Google Scholar: https://scholar.google.com/citations?hl=en&user=Ea9qpr0AAAAJ
Linkedin: https://br.linkedin.com/in/anny-manrich-20693129
In this article, we will address the query: “Are lentils and rice a complete protein?”. Furthermore, you will learn what is a complete protein and why combining rice and lentils can form a complete protein. This article will also give you information on health and risks of lentils and rice, and some ideas of recipes.
Are lentils and rice a complete protein?
Yes, the combination of lentils and rice create a complete protein (1,2). In fact, combining a legume and a cereal will create a complete protein. Found more information regarding this topic in the following sections!
What is a Complete Protein?
A protein is considered complete when it contains all essential amino acids. The human body needs 20 different amino acids; 11 of them are synthesized by your metabolism, but you must consume the other 9 amino acids (essential amino acids) through your food (1,2, 3).
You can find complete proteins in all animal-derived proteins such as meats, milk and dairy products, eggs, and fish. Normally, vegetable-derived proteins are deficient in one or more of the essential amino acids, hence, are considered as not complete proteins (3).
Why should you ingest complete proteins?
Amino acids are the building blocks of proteins, and proteins are the building blocks of human tissues like muscles and organs, immune cells, and enzymes used by your metabolism for food digestion, production of hormones, to produce energy, and many other functions (4).
So, if you do not consume an adequate quantity and quality of proteins, your body will not be able to do things correctly, including defending yourself against diseases; you will lose muscle mass; and if you are a child or adolescent, maybe your growth will be compromised (4).
What is the Nutritional Value of Lentils and Rice?
Even if lentils and rice are seeds or grains, they have very different nutritional value. Lentils have plenty of proteins (24 %), a moderate content of carbohydrates (63 %), and a minimum content of fats (1 %); the most important thing is that lentils are an excellent source of fiber (10 %) and minerals (5).
Regarding the protein quality, lentils (well, all legumes) lack Methionine and Cysteine, these are two essential amino acids that your body needs to produce essential molecules like glutathione, with potent antioxidant properties to protect you against diseases (3,6).
On the other hand, rice is more about carbohydrates (approximately 80 %), and in the case of the white rice, it does not have too much fiber (2 %) compared to the brown rice (3.6 %); however, rice also provides you with a modest quantity of proteins (6 %) and very little amount of fats (<1 %) (7,8).
The protein of rice, just like many other cereals, do not contain Lysine and Tryptophan, two essential amino acids that your body needs for growth and development (3,9).
Why Combining Lentils and Rice form a Complete Protein?
Combining lentils and proteins can create a complete protein because they complement each other. As it was described in the previous subheading, rice contains the amino acids that are missing in lentils, and vice versa (1,3). Think that is like a puzzle, both have one part missing, but they complement each other.
What are the Benefits of Lentils and Rice?
Consuming rice and lentils has a lot of health benefits (10,11) because they are a good source of minerals, fiber, and other types of molecules known as bioactive compounds that could improve your health. Some benefits are the following:
The fiber contained in lentils and rice helps to regulate your digestion; also, lentils have some sugars called oligosaccharides which feed your microbiota, improving your gut’s health (10).
Some of these “bioactive compounds” are very good for preventing cardiovascular diseases, for instance, saponins, tannins, and flavonoids in lentils are excellent antioxidants and for reducing your cholesterol levels in blood (11).
In the case of rice, unfortunately, all the bioactive compounds of it are discarded with the rice bran when industries process brown rice to obtain white rice (12).
What are the Risks and Precautions of Consuming Lentils and Rice?
Among the potential risks of lentils and rice, the most concerning are the presence of heavy metals or toxins. Some of these are the result of pollution, you should consider that every pollutant in the air, water, and soil eventually reaches us (13,14).
There are some studies that detected lead, arsenic, mercury, and cadmium but in small quantities; take into account that those quantities could vary if your region is very polluted or not. So you could check for the best brands of lentils and rice available in your country (13, 14).
Another thing to consider is that oligosaccharides of lentils are not digested by humans, so it is possible that once it reaches your intestine, it will be fermented and can cause flatulence or abdominal inflammation (15).
What Other Food Combinations form a Complete Protein?
You can improvise on the combination of cereals and legumes to create complete proteins, for example, you can use wheat, maize, or sorghum (as the cereal source) and combine them with legumes like pea, beans, cowpea, sesame, soybean, or chickpea (2, 3).
Here are some ideas of recipes to build a portfolio of dishes with lentils; you can add rice to those without any cereal in the recipe.
How to Prepare Lentils and Rice for Maximum Nutritional Value?
The best way to prepare lentils and rice to reach their maximum nutritional value is soaking your lentils for a few hours with plenty of water. This helps to break down those oligosaccharides and is less probable that makes you with abdominal inflammation (15).
Another tip you could adopt is to add a few drops of lime to your lentils. The ascorbic acid of lime will help your body to absorb the iron contained in the lentils (16).
Conclusion
In this article, we addressed the query: “Are lentils and rice a complete protein?”. Furthermore, you learned what is a complete protein and why combining rice and lentils can form a complete protein. This article also gave you information on health and risks of lentils and rice, and some ideas of recipes.
References
- Rafii M, Pencharz PB, Boileau K, Ball RO, Tomlinson C, Elango R, Courtney-Martin G. Metabolic Availability of Methionine Assessed Using Indicator Amino Acid Oxidation Method, Is Greater when Cooked Lentils and Steamed Rice Are Combined in the Diet of Healthy Young Men. The Journal of Nutrition, 2022, 152(6), 1467-1475.
- Temba MC, Njobeh PB, Adebo OA, Olugbile AO, Kayitesi E. The role of compositing cereals with legumes to alleviate protein energy malnutrition in Africa. Int J Food Sci Technol, 2016;51(3):543–54.
- Day L. Proteins from land plants – Potential resources for human nutrition and food security. Trends Food Sci Technol, 2013;32(1):25–42.
- Olson B, Marks DL, Grossberg AJ. Diverging metabolic programmes and behaviours during states of starvation, protein malnutrition, and cachexia. J Cachexia Sarcopenia Muscle, 2020;11(6):1429–46.
- FoodData central [Internet]. Usda.gov. [cited 26 Apr. 2023]. Available from: https://fdc.nal.usda.gov/fdc-app.html#/food-details/172420/nutrients
- Beaumont M, Blachier F. Amino acids in intestinal physiology and health. Adv Exp Med Biol, 2020;1265:1–20.
- FoodData central [Internet]. Usda.gov. [cited 26 Apr. 2023]. Available from: https://fdc.nal.usda.gov/fdc-app.html#/food-details/168883/nutrients
- Usda.gov. [cited 26 Apr. 2023]. Available from: https://fdc.nal.usda.gov/fdc-app.html#/food-details/169703/nutrients
- Xiao F, Guo F. Impacts of essential amino acids on energy balance. Mol Metab, 2022;57(101393):101393.
- Johnson N, Johnson CR, Thavarajah P, Kumar S, Thavarajah D. The roles and potential of lentil prebiotic carbohydrates in human and plant health. Plants People Planet, 2020;2(4):310–9.
- Kaale LD, Siddiq M, Hooper S. Lentil ( Lens culinaris Medik) as nutrient‐rich and versatile food legume: A review. Legum Sci, 2022.
- Saleh ASM, Wang P, Wang N, Yang L, Xiao Z. Brown rice versus white rice: Nutritional quality, potential health benefits, development of food products, and preservation technologies. Compr Rev Food Sci Food Saf, 2019;18(4):1070–96.
- Gu S-Y, Shin H-C, Kim D-J, Park SU, Kim Y-K. The content and health risk assessment of micro and toxic elements in cereals (oat and quinoa), legumes (lentil and chick pea), and seeds (chia, hemp, and flax). J Food Compost Anal, 2021;99(103881):103881.
- Sharafi K, Nodehi RN, Mahvi AH, Pirsaheb M, Nazmara S, Mahmoudi B, et al. Bioaccessibility analysis of toxic metals in consumed rice through an in vitro human digestion model – Comparison of calculated human health risk from raw, cooked and digested rice. Food Chem, 2019;299(125126):125126.
- Banti M, Bajo W. Review on Nutritional Importance and Anti-nutritional Factors of Legumes. Int. J. Nutr. Food Sci, 2020, 9(6), 138-149.
- Piskin E, Cianciosi D, Gulec S, Tomas M, Capanoglu E. Iron absorption: Factors, limitations, and improvement methods. ACS Omega, 2022;7(24):20441–56.
