LHASA, May 7 (Xinhua) -- For decades, Zhang Yuhong has viewed the microscopic world as a key to unlocking the vast potential of her homeland. A recipient of China's national May 1 Labor Medal this year, Zhang has dedicated her career to applying food microbial technology to modernize plateau specialties in southwest China's Xizang Autonomous Region.
Zhang, director of the institute of agricultural product development and food science at the Xizang academy of agriculture and animal husbandry sciences, and her team have recently restored "the flavor of childhood" in local yogurt. They accomplished this by selecting six functional microbial strains from over 1,000 microbial samples collected from across the region.
Born in Xizang in 1975, Zhang graduated from Southwest Agricultural University with a major in microbiology in 1998. The research landscape she entered was quite different from that of today. "Back then, there was no decent food laboratory in Xizang at all," she recalled.
After she was assigned to the academy's agricultural research institute to focus on plant protection, her early work involved a lot of microbiology-related cross-disciplinary tasks, such as pathogen isolation and disease analysis.
Undeterred by the lack of resources, she bought agar, meat peptone and other microbiological culture consumables out of her own pocket, transforming a corner of her office into a "mini-lab."
"At that time, I often went to the fields to collect leaf samples and cultivated strains like powdery mildew in my mini-lab," said Zhang. "Today, so much new equipment has been purchased that barely any spare space remains in our building."
In 2017, the institute of agricultural product development and food science was established. The institute boasts more than 10 specialized laboratories and a research team of over 60 members.
"With the improved facilities, we can truly 'write' our research papers on the vast land of the plateau," Zhang said.
In the past, locally produced highland barley baijiu (Chinese liquor) was made in small workshops. Under traditional production methods, the alcohol yield from highland barley was low, producing a maximum of about 50 grams of liquor per half kilogram of barley.
The plateau's dry climate and low humidity, along with the naturally sticky brewing environment of highland barley liquor, often caused the fermentation mash to compact and hinder microbial activity.
In 2019, Zhang's team launched a project focused on the development and industrial application of high-end highland barley liquor. Over the following three years, she led her team to monitor the boiling point changes at different altitudes.
By adjusting the length of the condenser tubes and the heating power, they identified the optimal temperature and distillation time for maximizing alcohol extraction while preserving the unique aroma of highland barley.
To observe the impact of low-temperature environments on the fermentation mash, Zhang often braved subzero temperatures at night in the laboratory's airing room, recording the humidity and viscosity changes of the mash every hour.
Her perseverance paid off. "Now, half a kilogram of highland barley can produce 165 grams of liquor," she said.
In 2023, Zhang's team embarked on a journey across the region to search for strains in order to restore the traditional flavor of yogurt. "Traditional Tibetan yogurt is served in iron basins by nomads in their tents. It is simple and clean, with a slightly sour dairy aroma," Zhang said.
Zhang traveled to remote villages, visiting the tents of nomads to collect warm yogurt samples bowl after bowl. "In the past, yogurt strains were mostly imported, while our own excellent local resources failed to develop into a robust industry," she said.
Over the following two years, the team experienced multiple instances of strain degeneration before finally selecting six stable, high-quality functional bacterial strains. These strains effectively retained the thick texture and unique flavor of traditional yogurt.
"This is the exact flavor of yogurt I ate when I was a child. I'm so moved that we've preserved this flavor using modern methods," said Phurbu Dorje, 34, a member of the research team.
Since the establishment of the new institute, Zhang's team has consistently focused on developing specialty food resources in the region, attracting investment and creating jobs for over 600 local households.
"Microbes are the invisible wealth of the plateau," she said. "What we need to do is use modern technology to awaken these dormant flavors and help Tibetan local specialty products reach broader markets." ■
