Saturday, May 18Food Security Matters

Turning Onion Leaves into Biomass: A Sustainable Solution for Agriculture

Agriculture has been the backbone of many economies across the globe, providing food, livelihoods, and resources. However, this vital sector faces numerous challenges, one of which is the management of agricultural waste. As the world’s population continues to grow, so does the amount of agricultural waste produced. In many countries, this waste poses environmental and economic challenges. Fortunately, innovative solutions are emerging to transform agricultural waste into valuable biomass resources. One such initiative is the endeavor to turn onion leaves, often discarded as waste, into a profitable and eco-friendly resource.

onion leaves waste
Discarded onion leaves

The Challenge of Agricultural Waste

Agricultural waste encompasses a wide range of materials, including crop residues, byproducts, and organic matter. The accumulation of these waste materials can strain local ecosystems and lead to environmental problems. In response to this challenge, the Department of Agriculture (DA) in the Philippines has taken the initiative to address the issue of agricultural waste, particularly in the onion industry.

Secretary Emmanuel Piñol, the head of the Department of Agriculture, recognized the need for increased competitiveness among onion farmers. To achieve this, he proposed strategies such as adopting new farming technologies and techniques to lower production costs and enhance farm yields. An innovative approach to tackle the problem was to investigate the potential uses of onion leaves, which are typically discarded as waste.

The Value of Onion Leaves

Onions (Allium cepa) are a staple in countless culinary traditions, valued for their distinctive flavor, nutritional content, and medicinal properties. In the Philippines, Nueva Ecija stands as the top onion-producing region, contributing significantly to the country’s onion production. Despite the importance of onions, the leaves and roots of the plant are typically left behind in the field after harvesting, resulting in the accumulation of organic waste.

These discarded onion leaves become breeding grounds for pests and insects, causing potential contamination and environmental hazards. The foul odor emanating from decaying onion leaves adds to the concerns related to their disposal. Recognizing the untapped potential in these agricultural wastes, Secretary Piñol instructed the Bureau of Agricultural Research (BAR), the national R&D arm of DA, to explore alternative uses for onion leaves.

Transforming Waste into Opportunity

The BAR took up the challenge and collaborated with various R&D implementing agencies, including the University of the Philippines Los Baños (UPLB), to develop an integrated research program. Their goal was to create a package of technologies (POTs) for the utilization of onion leaves, transforming them into different products that could provide additional income to farmers.

Dr. Myra G. Borines, the project leader from UPLB, spearheaded the efforts to unlock the potential of waste onion leaves. The research aimed to create high-value products from these leaves, increasing the profitability of onion farming while reducing postharvest losses. The team explored the possibility of using onion leaves as a spice in local dishes, following proper research and processing techniques.

Overcoming Challenges

One significant challenge the research team faced was the presence of pesticide residues in onion leaves due to the plant’s vulnerability to various pests. Onion growers commonly use chemical pesticides to protect their crops. To make onion leaves safe for consumption, various methods were explored to remove these pesticide residues. Techniques included washing with tap water, soaking in a vinegar solution, boiling, washing with a liquid detergent solution, and soaking in a baking soda and lemon juice mixture.

In addition to addressing pesticide residues, the researchers conducted storability studies to determine how long onion leaves could be stored. Factors affecting the shelf-life of onion leaves were considered, and the bioactive components of onion leaves were analyzed to explore their potential applications.

Transforming Onion Leaves into New Products

The research team explored multiple dehydration techniques to enhance the shelf-life of onion leaves. Dehydration, the process of removing moisture from food products, was evaluated through four methods: sun drying, conventional drying, freeze drying, and vacuum drying. Results indicated that conventional drying and vacuum drying were preferred methods for preserving essential phytochemicals in onion leaves. Freeze drying, while preserving color and appearance, also successfully reduced moisture levels.

The team’s efforts led to the development of several products derived from onion leaves, including dried onion leaves, powdered onion leaves, pickled onion leaves, onion leaves extract, and vacuum-fried onion leaves. These products can be further processed and used as ingredients in various culinary applications, ranging from teas and seasonings to garnishes and snacks.

Impacts and Future Prospects

The transformation of waste onion leaves into valuable products not only addresses the problem of postharvest losses but also holds the potential to enhance the productivity and income of onion farmers. This initiative presents a significant opportunity to revolutionize the onion industry by providing sustainable solutions for managing agricultural waste.

As the world continues to grapple with agricultural waste challenges, this pioneering project serves as a beacon of hope, demonstrating how innovative thinking and research can convert agricultural waste into a valuable resource. The successful transformation of onion leaves into new and profitable products is a testament to the potential that lies within our agricultural systems to create a more sustainable and prosperous future.

Frequently Asked Questions  About Biomass

Biomass is a renewable energy source that has gained popularity as a sustainable alternative to fossil fuels. It involves using organic materials to produce energy. Here are some frequently asked questions about biomass:

1. What is biomass?

Biomass refers to organic materials derived from plants and animals. These materials can be used to produce energy through various processes, such as combustion, gasification, and fermentation.

2. What types of materials are considered biomass?

Biomass can include a wide range of materials, such as wood, crop residues, agricultural waste, animal manure, and even dedicated energy crops like switchgrass and willow trees.

3. How is biomass used to produce energy?

Biomass can be converted into various forms of energy, including heat, electricity, and biofuels. The most common methods involve burning biomass to produce heat or steam, which can then be used to generate electricity, or converting it into biofuels like ethanol and biodiesel.

4. Is biomass considered a renewable energy source?

Yes, biomass is considered a renewable energy source because it involves using materials that can be replenished through natural processes, such as the growth of plants and trees. As long as the rate of consumption does not exceed the rate of replenishment, biomass is sustainable.

5. What are the environmental benefits of biomass energy?

Biomass is often considered a more environmentally friendly alternative to fossil fuels because it produces fewer greenhouse gas emissions. It also helps reduce waste by using organic materials that might otherwise end up in landfills.

6. Are there any drawbacks to using biomass for energy?

One drawback of biomass is that its production and use can have negative environmental impacts, such as deforestation or competition for land with food crops. Additionally, burning biomass can release pollutants and particulate matter into the air if not properly controlled.

7. Can biomass be used for heating in homes and businesses?

Yes, biomass can be used for heating in the form of wood pellets, chips, or logs. It’s a common source of renewable heat and is often used in stoves and boilers for residential and commercial heating.

8. What is the potential for biomass in reducing dependence on fossil fuels?

Biomass has the potential to significantly reduce dependence on fossil fuels, particularly in sectors like transportation and heat generation. It can be used to produce biofuels that can replace gasoline and diesel, and it can also be used for combined heat and power (CHP) applications.

9. How is biomass different from bioenergy?

Biomass refers to the organic materials themselves, while bioenergy is the energy produced from those materials. Bioenergy encompasses various forms of energy, including electricity, heat, and biofuels, derived from biomass.

10. Are there any technological advancements in biomass utilization?

Advancements in technology have made biomass energy production more efficient and environmentally friendly. Research is ongoing to improve conversion processes, reduce emissions, and make better use of different types of biomass.

Biomass is a versatile and sustainable energy source that plays a vital role in reducing greenhouse gas emissions and moving towards a more sustainable energy future. As technology continues to advance, biomass is likely to become an even more significant part of the renewable energy landscape.


Bureau of Agricultural Research
Myra G. Borines, Ph.D
Project Leader/ Associate Professor 5
Department of Chemical Engineering, CEAT
University of the Philippines Los Baños (UPLB)
College, Laguna, 4031
Phone: (049) 536-2315
Email: [email protected]

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