Posts Tagged: Selina Wang

UC ANR publishes first-ever manual on olive production for oil

Growers, UC Cooperative Extension researchers offer guidance on producing high-quality olives

Facing a deluge of lower-price products from Europe, the California olive oil industry is doubling down on its clear-cut competitive edge: the consistent and bona fide quality of its oil.

“Olive Production Manual for Oil,” a new book published by University of California Agriculture and Natural Resources, aims to help California olive growers maximize that advantage.

“It's a tough market to compete in, but I think the way to win for California is to compete on quality,” said book co-editor Selina Wang, a UC Cooperative Extension specialist in the UC Davis Department of Food Science and Technology. “The quality of California olive oil is unmatched, but you can't make good quality olive oil with bad fruit, so the goal is to get more fruit from the trees – and for the fruits to be high-quality fruit.”

The 273-page manual, available for purchase online, is the first of its kind in the U.S. While some parts of the book are specific to California (which grows nearly all of the olives for domestically produced olive oil), most of the material would be useful to producers in other states, Wang noted.

“Through our conversations with growers, it became clear to us that a manual like this – not a scientific publication but a manual that is easy to follow, written in language that is accessible, and with pictures and illustrations – would be really helpful to the growers,” she said.

Growth of California olive oil industry necessitated creation of manual

Aside from a book focused predominantly on table olives and another on organic olive production (by UCCE farm advisor emeritus Paul Vossen), there was no one-stop, comprehensive resource on the bookshelf for oil olive growers. The need for such a manual had become more acute as oil olives replaced table olives in California orchards during the last 20 years.

Whereas harvesting by hand was historically cost-prohibitive, the introduction of super-high-density planting systems in 1999 made oil olive production more economically feasible. Mechanical pruning and harvesting of new cultivars (Arbequina, Arbosana and Koroneiki) – specifically bred for these densely planted orchards – led to the rapid expansion of oil olives in the state. According to a U.S. Department of Agriculture report, California olive oil production jumped from 2 million pounds in 2006 to an average of 21 million pounds in 2021–23. 

With about 37,000 acres of oil olives planted across California, the Olive Oil Commission of California saw the need to support the production of this manual. Championed by Dan Flynn, founder and executive director emeritus of the UC Davis Olive Center, Wang and co-editor Louise Ferguson outlined the contents of the book. They then sought out a mix of growers and industry professionals and UCCE advisors and specialists to write its chapters.

“Most of the information is data-based, from people who are working with the olives,” said Ferguson, a UC Cooperative Extension pomologist at UC Davis. “This is the first data-based olive oil production manual we've had.”

Manual infused with firsthand insights, practical recommendations

Hard-earned experience taught growers a valuable lesson that is conveyed in the book – the need to hand-prune. While mechanical pruning helps control the size of the trees, some hand-pruning is still required to allow light to filter to the leaves. Failing to do so leads to a dramatic decrease in yield.

“That happened in many of the orchards that were inexperienced in these new cultivars and new super-high-density planting systems,” Ferguson said.

She added that other key topics in the manual include irrigation management in a water-constrained state, nitrogen management, harvest timing and orchard site selection. Choosing a good spot for planting is crucial in this era of extreme climate volatility, Ferguson noted, as olive trees are significantly affected by temperature shocks in spring (fruit set) and fall (harvest).

For Wang, another overarching theme in the manual is the importance of testing. Testing the soil, water and leaves provides critical data that growers can use to adjust their inputs and production practices for optimal profitability.

“You may spend a couple hundred dollars on the lab work, but it will pay off, for sure – you're going to increase the health and productivity of your trees,” Wang explained. “Oil olive growers are paid based on the oil content in their fruit; you not only want to have a lot of fruit on the trees, you want to make sure that your fruit are accumulating oil.”

California oil olive growers, practices continue to evolve

Wang and Ferguson hope their book will help California producers compete more effectively in the global marketplace. Currently, about 90% of the olive oil consumed in the U.S. is imported from Mediterranean countries, due primarily to the lower price point. In that region, producers tend to harvest riper olives that produce oil at a greater volume but lesser quality.

In contrast, California growers harvest earlier and produce oil that is higher quality (with more flavor and more antioxidants) and far exceeds accepted standards for “extra virgin olive oil.”

According to Wang, California olive oil mills have nearly maximized their efficiency, and the growth opportunity for the industry is in the orchards: to optimize practices to produce more fruit, and to plant more trees. Wang said the new manual can help on both fronts.

“Just like for other crops, focusing on quality – while increasing efficiency and productivity, and therefore profitability – is the name of the game,” she said.

Ferguson also stressed that knowledge continues to evolve and urged growers to reach out to the editors and chapter authors with their experiences.

“Most of the authors are in California and they're working,” she said. “So if you start to notice things that are different, or you want more information or something is not clear, the authors are available.”

The manual can be purchased at https://anrcatalog.ucanr.edu/Details.aspx?itemNo=3559.

Lawn-pocalypse! Surviving Drought

Ah, summer! The season of sunburns, pool parties, and… lawn droughts. If your once lush, green carpet now looks like a crunchy brown doormat, you're not alone. Let's dive into why your yard is staging a dramatic death scene and what you can do to...

Bermuda grass and weeds overtaking drought stressed turf grass.

A patch of former lawn, mostly dead, with a few green weeds and Bermudagrass

Grape seeds, stems and skins can reduce dairy cattle emissions

Low-cost wine industry additive also improved feed efficiency and milk quality

Researchers at University of California, Davis, added fresh grape pomace left over from winemaking operations to alfalfa-based feed for dairy cows and found that methane emissions were reduced by 10% to 11%.

The preliminary findings could offer a low-cost sustainable pathway for vineyards to reduce waste while helping dairy operations maintain quality while cutting back on emissions of methane, which is a powerful greenhouse gas.

“This is the first time anybody has shown that this can work in California,” said Ermias Kebreab, an animal science professor and associate dean of global engagement at UC Davis. “You're reducing emissions, you're improving the quality and it may also reduce the cost of production.”

The pilot research project, which will be detailed in a paper later this year, also found that mixing in grape pomace improved feed efficiency and increased healthful fats, said Selina Wang, an associate professor of Cooperative Extension in small scale fruit and vegetable processing.

“We found that the feed with the additive of grape pomace changed the fatty acid composition of the milk and, in particular, increased the polyunsaturated fats, which are the main fats in grape pomace,” Wang said. “This suggests that supplementing the feed with an optimal fatty acid profile may have positive impact on the fatty acid profile of the milk and increase their health benefits.”

Symbiotic commodities?

In 2022, California was the leading dairy producer in the country, generating $10.40 billion in sales, while 90% of wine production came from the Golden State, with a market value of $5.54 billion.

Processing grapes for wine generates thousands of tons of waste in the form of grape pomace, which consists of leftover seeds, skins and stems. Dairy and livestock are responsible for more than half of the state's methane emissions, owed largely to cow burps.

They are the top two agricultural commodities in California, according to state production statistics, and reducing waste and emissions for both industries are key to the state meeting its climate goals.

Tannins for emission reductions

Wine grapes are high in fats and tannin, which is known to reduce methane emissions, so Kebreab sought to test if adding grape pomace to feed could have a positive effect while not adversely affecting production.

“It's a byproduct that's not being used much,” he said. “This is something that can be included in our efforts to try to reduce emissions.”

A mix of feed options

To do the research, scientists worked with Holstein dairy cows and gave the animals feed consisting of alfalfa, wheat, almond hulls, cottonseed and grain. After two weeks, the cows were split into three groups: A control group with no change in diet, another where the feed combination included 10% grape pomace and a third that received 15% grape pomace.

Every four weeks, the cow groups would change feed combinations.

They were fed twice daily by postdoctoral students and interns, and emissions were monitored daily. Milk production was documented in the morning and evening and milk samples were collected weekly to analyze for fat, protein, lactose and other measurements, which showed no differences between the control and other groups.

Methane and hydrogen emissions were reduced compared with the control group, suggesting that grape pomace reduced enteric emissions without affecting production.

“I think the dairy industry will be very interested in this,” Kebreab said. “Sometimes when you're using additives, they have palatability issues. With grape pomace, they absolutely love it.”

Next on the list is a trial with olive pomace and working to understand the mechanism that reduces emissions. “If we have a better understanding of the mechanisms, we can select the feed additive or a mix of feed additives to reduce dairy cattle emissions and make dairy milk healthier while making use of the agriculture byproducts,” Wang said. “There's a lot of room to grow in this space and we're excited about this work.”

The research was supported by the California Dairy Research Foundation.

This article was first published on the UC Davis news site.

 

Nearly 70% of private label avocado oil rancid or mixed with other oils

Researchers identify key markers to help professional retail buyers choose authentic products

Avocado oil has become a popular choice for many people in recent years because of its heart-healthy benefits and versatility in cooking. However, not all avocado oil products on store shelves are created equal. Some products are labeled as “pure” avocado oil when they contain other oils or additives. No enforceable standards defining the chemical and physical characteristics of avocado oil exist yet.

Researchers at the University of California, Davis, analyzed samples of 36 private label avocado oil products and graded them based on quality and purity. Private label products are made by a third-party processor and sold under a grocery store or retailer brand label. Their findings, published in the journal Food Control, show that 31% of the samples tested were pure, and 36% were of advertised quality. Quality refers to whether the oil is fresh or has gone bad due to aging, heat or light exposure. For purity, researchers measured fatty acids, sterols and other components that differentiate avocado oil from other oils.

The study included oils purchased from 19 retailers in the U.S. and Canada with various price points. They found that lower-priced oils were more likely to be tainted with other oils.

“We found that low-cost products indicate a higher probability for adulteration, but high cost didn't guarantee purity or quality,” said Selina Wang, associate professor of Cooperative Extension in the Department of Food Science and Technology. She and Hilary Green, a postdoctoral researcher at UC Davis, co-authored the paper.

Researchers also identified certain chemical markers in avocado oil that professional retail buyers can use to make more informed decisions when it comes to choosing suppliers. This way, consumers can feel confident about the products they buy.

This is the second comprehensive study conducted by UC Davis researchers on the quality of avocado oil sold in the U.S. The first study released in 2020 found that many of the test samples were of poor quality, mislabeled or adulterated with other oils.

“This study demonstrates that although progress is being made in standard development since our first market study in 2020, there are still issues with purity in avocado oil and these issues extend significantly into private label oils,” Wang said.

Avocado oil standards

Since the release of the first UC Davis study, Wang said there's been a coordinated effort by researchers, industry leaders and government agencies to establish enforceable standards. The Avocado Oil Expert Group was formed in collaboration with the American Oil Chemists' Society to discuss potential standards and future research projects.

Wang's research group has been studying how natural factors like different types of avocados, harvest times, geographic origins and processing methods could affect the chemical composition of avocado oil. They want to create standards that will accommodate natural variations while detecting any adulterations.

Wang hopes that the study's findings will contribute to the establishment of standards that benefit both consumers and avocado oil producers who want to compete in a fair market.

“I'm very optimistic for the future of the avocado oil industry,” Wang said. “It's a high-value product with high consumer demand, similar to what I saw with olive oil 10 years ago. Olive oil quality and purity have improved significantly, which is where I see avocado oil going, if we can establish fair standards and eliminate fraudulent products.”

Climate-Change Resources

University of California UC ANR Green Blog (Climate Change and Other Topics) https://ucanr.edu/blogs/Green/index.cfm?tagname=climate%20change (full index)

Examples:

     -  Save Trees First: Tips to Keep Them Alive Under Drought https://ucanr.edu/b/~CdD 

     - Landscaping with Fire Exposure in Mind: https://ucanr.edu/b/~G4D

     - Cities in California Inland Areas Must Make Street Tree Changes to adapt to Future Climate  https://ucanr.edu/b/~oF7

Drought, Climate Change and California Water Management Ted Grantham, UC Cooperative Extension specialist (23 minutes) https://youtu.be/dlimj75Wn9Q

Climate Variability and Change: Trends and Impacts on CA Agriculture Tapan Pathak, UC Cooperative Extension specialist (24 minutes) https://youtu.be/bIHI0yqqQJc

California Institute for Water Resources (links to blogs, talks, podcasts, water experts, etc.) https://ciwr.ucanr.edu/California_Drought_Expertise/

UC ANR Wildfire Resources (publications, videos, etc.) https://ucanr.edu/News/For_the_media/Press_kits/Wildfire/ (main website)

      -UC ANR Fire Resources and Information https://ucanr.edu/sites/fire/ (main website)

            -Preparing Home Landscaping https://ucanr.edu/sites/fire/Prepare/Landscaping/

UC ANR Free Publications https://anrcatalog.ucanr.edu/ (main website)

- Benefits of Plants to Humans and Urban Ecosystems: https://anrcatalog.ucanr.edu/pdf/8726.pdf

 -Keeping Plants Alive Under Drought and Water Restrictions (English version) https://anrcatalog.ucanr.edu/pdf/8553.pdf

  (Spanish version) https://anrcatalog.ucanr.edu/pdf/8628.pdf

-  Use of Graywater in Urban Landscapes https://anrcatalog.ucanr.edu/pdf/8536.pdf

-  Sustainable Landscaping in California https://anrcatalog.ucanr.edu/pdf/8504.pdf

 

Other (Non-UC) Climate Change Resources

Urban Forests and Climate Change. Urban forests play an important role in climate change mitigation and adaptation. Active stewardship of a community's forestry assets can strengthen local resilience to climate change while creating more sustainable and desirable places to live. https://www.fs.usda.gov/ccrc/topics/urban-forests

Examining the Viability of Planting Trees to Mitigate Climate Change (plausible at the forest level) https://climate.nasa.gov/news/2927/examining-the-viability-of-planting-trees-to-help-mitigate-climate-change/

Reports and other information resources coordinated under the auspices of the United Nations and produced through the collaboration of thousands of international scientists to provide a clear and up to date view of the current state of scientific knowledge relevant to climate change. United Nations Climate Action

Scientific reports, programs, action movements and events related to climate change. National Center for Atmospheric Research (National Science Foundation)

Find useful reports, program information and other documents resulting from federally funded research and development into the behavior of the atmosphere and related physical, biological and social systems. Search and find climate data from prehistory through to an hour ago in the world's largest climate data archive. (Formerly the "Climatic Data Center") National Centers for Environmental Information (NOAA)

Think tank providing information, analysis, policy and solution development for addressing climate change and energy issues (formerly known as the: "Pew Center on Global Climate Change"). Center for Climate & Energy Solutions (C2ES)

Mapping Resilience: A Blueprint for Thriving in the Face of Climate Disaster. The Climate Adaptation Knowledge Exchange (CAKE) was launched in July 2010 and is managed by EcoAdapt, a non-profit with a singular mission: to create a robust future in the face of climate change by bringing together diverse players to reshape planning and management in response to rapid climate change. https://www.cakex.org/documents/mapping-resilience-blueprint-thriving-face-climate-disaster

Cal-Adapt provides a way to explore peer-reviewed data that portrays how climate change might affect California at the state and local level. We make this data available through downloads, visualizations, and the Cal-Adapt API for your research, outreach, and adaptation planning needs. Cal-Adapt is a collaboration between state agency funding programs, university and private sector researchers https://cal-adapt.org/

Find reports, maps, data and other resources produced through a confederation of the research arms of 13 Federal departments and agencies that carry out research and develop and maintain capabilities that support the Nation's response to global change. Global Change (U.S. Global Change Research Program)

The Pacific Institute is a global water think tank that combines science-based thought leadership with active outreach to influence local, national, and international efforts to develop sustainable water policies. https://pacinst.org/our-approach/

Making equity real in climate adaptation and community resilience policies and programs: a guidebook. https://greenlining.org/publications/2019/making-equity-real-in-climate-adaption-and-community-resilience-policies-and-programs-a-guidebook/ 

Quarterly CA Climate Updates and CA Drought Monitor Maps (updated each Thursday) https://www.drought.gov/documents/quarterly-climate-impacts-and-outlook-western-region-june-2022

 

 

 

 

Read more