When you need a lunch on the go or something quick for a dinner, few things are as convenient and versatile as wraps or tortillas.
They're also a popular emergency pantry food, thanks to their incredibly long shelf-life, even at room temperature.
But how do wraps last so long and are they actually healthy?
How come wraps last so long?
The longevity of wraps is thanks to several factors, including their packaging, pH and moisture levels as well as ingredients, says Jayani Chandrapala, Associate Professor in Food Science at RMIT University.
"It depends on the moisture content that the wraps are within, and also the air levels, because wraps are in airtight sealed bags."
Anti-fungal and antimicrobial preservatives are used to inhibit the growth of microbes, such as mould.
Some preservatives commonly added to wraps include propionic acid, calcium propionate, sodium propionate, sorbic acid and potassium sorbates, Dr Chandrapala says.
Acids, such as fumaric acid, are used to manipulate pH levels.
If a company wants to use less preservatives, the other conditions, mainly moisture and air levels, must be balanced carefully, Dr Chandrapala says.
"There are other pros and cons to how the tortilla looks like and how dry it is," she says.
"All these factors together, depending on which processing methods they (the manufacturer) are using, is what actually lets them last long."
Are wraps healthy?
Clinical Nutritionist Renee Bailey says wraps themselves are not that healthy, but the answer also depends on the person and what they're looking for out of their diet.
"The wrap itself doesn't have a lot of nutritional value," she explains.
"Most of them are mainly grains, so wheat or rye or barley or one of the other ones, and most grains convert in the body straight to glucose."
Glucose is what the sugar in the blood is called. It comes from eating carbohydrates and is a main source of energy for the body.
"[Wraps] don't really have any protein in them, they don't have a lot of vitamins and minerals, but what you put on them makes the biggest difference," Ms Bailey says.
"What you'd want to do is have lots of salad and veggies, some protein, like some chicken or tuna, and then some good fats like avocado or feta cheese. That's going to actually balance them out and make sure that there's a lot of nutrient rich food that's wrapped up in the wrap."
"You're just kind of using them as a delivery vessel."
It also matters how often you eat them and the quality of the wrap you buy, she says.
"It's about balance. If you're eating them three or four times a day, that's probably not great. If you're having them two or three times a week, that's probably fine if your overall diet is balanced and you are a healthy person overall."
Are some healthier than others?
When picking out a packet of wraps at the shops, whole grain wraps will have a lower glycaemic index — which is used to measure how much a specific food increases your blood sugar levels — as well as more fibre, Ms Bailey says.
Her advice is to look for the ones with fewer ingredients – that includes the preservatives mentioned before – and less sugar.
The more additives there are in a product, the more processed it is, and that can cause reactions in some people, Ms Bailey says.
"The more processed something is, the less nutritious it is, normally, because more processing brings it further away from its natural form."
Dr Chandrapala says the preservative question comes down to dosage, and most products only use "tiny amounts" of them.
"If you have small amounts, it shouldn't be a problem at all. But then over time, it can be an cumulative effect."
Still a good emergency food
If you need a food option that lasts a long time and can be grabbed out of the cupboard in an emergency, wraps are "a good alternative", Ms Bailey says.
"They're great as quick and easy pizza bases for kids, so you can put some ham and cheese and veggies on them and pop them under the grill and make like a little mini pizza out of them, and that can be a healthy alternative to the more processed take away pizzas."
Nori – dried sheets of seaweed paper – is another long-lasting pantry alternative to wraps that she often recommends to her clients.
"[They] have a little bit less ingredients in them that aren't good for you and have a little bit more nutrients in them."
Another option is dried rice paper sheets, Ms Bailey says.
But food advice is never "black and white", and she says the best nutritional advice depends on your individual circumstances.
