Turning up the heat

By Matthew da Silva (BA (Hons) ’85 MMediaPrac (Merit) ’08

Photo of Mark Peacock and Marcel de Wit

Mark Peacock and Marcel de Wit

From their origins in the New World, chillies failed to spark much interest in Europe after Columbus brought them back, but they took root in the African colonies of Portugal and Spain, whence they were taken to the Portuguese colony of Goa, on the west coast of the subcontinent. From Goa it was but a short hop to Southeast Asia, where a thriving peppercorn culture meant chillies were quickly embraced by peoples already familiar with the concept of heat-plus-spice.

The heat in chillies led to a profusion of varieties as growers in different countries selected the trait of hotness. It’s curious because the heat in capsaicin – the active constituent of chillies – is actually designed by nature to discourage mammals from eating the fruit, says Mark Peacock (BHortSc ’10) (above).

He says it is an evolutionary advantage for chillies to produce capsaicin because the chemical deters mammals from eating the fruit while birds are attracted to them as they don’t detect capsaicin. “In birds, stomach acid breaks down a hydrophobic layer on the seed and allows it to take in water and germinate,” says Mark, “while in the mammalian stomach the seed is essentially destroyed”.

For his fourth-year thesis Mark used genetic analysis to investigate the differences between what were then the world’s hottest chillies, the Bhut Jolokia and its cousin, the Bih Jolokia. He located polymorphisms between the two varieties at markers on six different chromosomes using three different molecular genetic techniques.

Guinness World Records first recognised the hottest chilli in 1994, when the title was awarded to the Red Savina Habanero (1994 special), developed by GNS Spices of Walnut, California. It measured 570,000 Scoville units. The current record holder, the Naga Viper, registers 1,382,118 Scoville units. (The Scoville scale is named after American Wilbur Scoville who invented the measurement in 1912.)

Now, NSW Central Coast company, The Chilli Factory is marketing the Trinidad Scorpion Butch T, which registers 1,463,700 Scoville units, now the Guinness record holder.

Everything I learned throughout the degree I tried out on my little plants in the backyard

Mark Peacock became involved with The Chilli Factory after his thesis supervisor, Adjunct Professor Nick Derera of the University’s Plant Breeding Institute, suggested he contact owner Marcel de Wit.

De Wit gave him samples and helped him with work experience requirements for his degree and soon recognised the student’s special knowledge. De Wit sought his advice as they pushed ahead to the goal of developing the world’s hottest chilli.

“It was all trial and error, and I felt like I took their trial and error and gave scientific explanations why things would work and what would work better,” says Peacock.

His advice covered such aspects as watering frequency, row spacing, fertilisation frequency, the different fertilisers available, light conditions, and even which potting mixes to use.

“I think, if anything, I helped fine-tune a lot of the processes,” says Peacock, who chose to study the Bhut Jolokia because it was “new and exciting”, although he also grew chillies at home.

“Everything I learned throughout the degree I tried out on my little plants in the backyard,” he says. “They just happened to be chillies which, I suppose, were easy plants to grow and I loved eating the fruit.

“We were asked if we’d like to do something different, like something crazy. ‘Pick your own topic and you’ll enjoy it more.’ So I thought, ‘I’m going to do the world’s hottest chilli’.”

He now works as a researcher developing biocontrol products for multinational agribusiness Becker Underwood at their facility in Somersby near Gosford. Peacock’s passion for plant breeding turned out to be an asset as the company manufactures biologicals such as rhizobial inoculants for use in agriculture.

“It was a bloody great feeling, actually. I was really excited. I really wanted to work in the industry. It was luck, but Sydney gave me the best opportunity.”