Customers entering the small Hawaiian Sweet Potato Factory are enveloped by the earthy scent of roasting sweet potatoes and baking bread. If the aroma isn’t tempting enough, the rich autumnal colors of the food and drink will be.

The uber-healthy root vegetable is in everything from purple-hued smoothies and sandwich bread, to golden yellow scones and tarts, combined with other local ingredients, like pineapple, haupia and mango.

>> About the business: Opened across the street from Ala Moana Center last August, this is the first Hawaii factory/deli for Japan-based Shirohato USA. The company’s tagline is “Designing to Spread Goodness of Sweet Potatoes Worldwide.”

A farmer in Waialua grows a golden yellow potato labeled Hareiwa Kintoki specifically for Shirohato; a small Hilo farm provides a purple variety similar to the Okinawan potato, named Beni Aloha. Eventually the company hopes to build a full-sized factory on the Big Island to ship both types and more to Japan and other parts of the globe, General Manager Issei Nakada said.

The company already processes about 2 tons of potatoes every week, and one day hopes to grow a brand of potato from each island, Nakada said.

You’d think Japan could simply import purple sweet potatoes from Okinawa, but Nakada said Japan’s trade regulations prohibit that. Potatoes from Hawaii cannot be sent raw; so they are aged, baked and frozen at the factory before shipping, he said. So far two 15-ton shipments of the purple have gone to Japan.

At this start-up stage, the small location on Kapiolani Boulevard consists of the kitchen and a cheerful deli/bakery.

The potatoes are ripened for a few weeks in a refrigerated, glass-doored “aging cellar,” until their sugar levels peak. This sets them apart from other potatoes, Nakada said.

“We age and ripen them, so they are darker in color and sweeter.”

>> About the food: Most of the food and drinks are made with the purple potatoes, about a ton a week. The golden sweet potatoes with red skin come in less frequently, from Twin Bridge Farms in Waialua.

Manager Midori Ohashi said the best-sellers are the simple baked potatoes, yellow or purple, at $1.50 per 100 grams (3.5 ounces). They can be eaten out of hand or taken home to become part of the family dinner. Sweet potato fries in both colors are also popular at $3.50.

Bread is either made with a potato powder, or potato bits added to the batter. Baker Jan Rivera makes pies, scones, bread, tarts and onion bread, averaging $4.

“Little kids are always skeptical until they try the pastry, and they realize, oh, it’s really sweet,” he said. “The yellow potato is a lot sweeter and creamier than the purple,” but the yellow is limited in supply.

An eye-catching pie cries out to be tasted, with contrasting colors of the purple sweet potatoes, pineapple slices fanned out on top, coconut shavings and macadamia nuts as a garnish.

Unlike a typical apple pie, the contents aren’t held together with a syrupy sauce, but with a sweet potato paste, so it’s practically a health food — except for the buttery, crumbly crust.

Based on a recipe from Japan, it’s not particularly sweet, but a scoop of vanilla ice cream would put it into the dessert category. A whole pie is $20; a slice, $4.

Sandwiches made with purple potato bread come with veggie, turkey, roast beef, chicken and kalua pork fillings, and are packed with fresh local vegetables, priced $6 to $8.50.

Fruits and vegetables are mixed into potato smoothies, $4.50 to $5.50. Royal Purple, the most popular, is made with blueberries and acai.

>> Grab and go: Call ahead or order at the counter. Several small tables are available inside. Park on the street, or in nearby lots.

Grab and Go focuses on takeout food, convenience meals and other quick bites. Email ideas to crave@staradvertiser.com.