Calum Henderson: Sisters' heart and Seoul on show in series debut

MasterChef New Zealand was axed by TVNZ after its fifth series in 2014, the year it was won by a pair of self-taught sisters from Maketu, a small town on the Bay of Plenty coast. TVNZ probably decided to quit while it was ahead: it was unlikely the show would ever top Karena and Kasey Bird.

Like Nadia Lim and Chelsea Winter before them, the Birds were crowd-pleasing winners, and have since gone on to bigger and better things. Their first television series, Karena and Kasey's Kitchen Diplomacy, debuted on TV One on Sunday night.

In each episode they travel to a different part of the world to immerse themselves in local food culture and, oddly, talk to a handful of New Zealand diplomats. At the end of each episode they prepare dishes for local dignitaries and food bloggers, fusing local recipes with New Zealand ingredients.

Most places they will be visiting for the first time, but in the first episode they travelled to South Korea, where Karena once won a youth Taekwondo tournament. "Last time I was here I didn't eat anything," the elder sister admitted in the taxi from the airport. "I basically ate instant noodles the entire time."

The duo may have risen to the rank of celebrity chefs since winning MasterChef but they still possess a raw, disarming charisma. In Seoul they talked about the food the way real people talk about food, they laughed and joked and did the Gangnam Style dance; time after time sidestepping celebrity chef cliches.

At Gwangjang Market, Kasey was encouraged to sample various delicacies, including a Korean blood sausage "stuffed with rice and pig's blood". Where most TV chefs roll their eyes back in ecstasy and purr "mmm, delicious" at everything they taste, Kasey's eyes instead widened in horror and she frantically shook her head. "That's not for me."

The sisters' honesty and openness helps set Kitchen Diplomacy apart from the countless other travel and cooking shows on television.

The sisters' honesty and openness helps set Kitchen Diplomacy apart from the countless other travel and cooking shows on television. While Kasey was at the markets, Karena spent the morning learning from a kimchi master called Mrs Lee, and despite the language barrier the two seemed to bond on a sort of spiritual level over big bowls of seasoned vegetables.

An overwhelmed Karena fought back tears as she tried to articulate what the experience meant to her: "It highlights how important it is to learn the traditional things from your parents and your grandparents," she explained, "how important it is to learn from your own culture."

The sisters' own Maori culture was woven effortlessly through the episode - little things like the game of Hei Tama Tu Tama they played to decide who would go to the markets, as well as in the food they prepared in a typically MasterChef frenzy for the New Zealand Ambassador and guests.

This part, while providing the impetus to the show, represented an unusual change of pace from the rest of the episode. The diplomacy angle also seemed a little incongruous, almost as if it could be a different show altogether, though the two New Zealand diplomats Karena and Kasey met - Ambassador Clare Fearnley and Deputy Head of Mission John Riley - were good value.

Riley explained how Pokarekare Ana had become well known in South Korea following the Korean War, and the three of them, huddled around a barbecue table, spontaneously began singing the first verse of that beautiful, timeless melody. Then they stopped and laughed, and Karena said: "Let's stick to the cooking eh?"