London - From banana peel to melon pips and onion skins – believe it or not, some of the most powerful nutrients in our fruit and veg are in the bits we throw away.
“Many fruits and vegetables have skins and leaves that are more colourful than the flesh,” says dietitian Dr Sarah Schenker.
“This is a good indication they contain high levels of powerful compounds such as protective antioxidants. Peel, stalks, leaves and cores are packed with dietary fibre, too.”
But how can you make watermelon rind and broccoli stalks tasty?
We asked Dr Schenker to reveal the pips and peelings we should be eating, and then challenged chef Aldo Zilli to come up with ways to make them taste delicious.
BANANA PEEL CHEESECAKE
It may look tough and leathery, but you can eat banana skin, provided you cook it or put it through a juicer.
In a recent study, researchers found banana peel extract to be rich in seratonin, a mood-balancing chemical that has the potential to ease depression.
It was also shown to be rich in lutein, a protective antioxidant vitamin that helps to protect eye cells from ultra-violet light - the leading cause of cataracts.
ALDO'S TIPS: Remove the tough top and bottom ends of the skins, then soak for several days to soften them. Change the soaking water each day.
Once the water runs clear, boil, strain and puree the skins to add a sweet, date-like flavour to cakes and cheesecake.
To make banana peel cheesecake, mix 175g crushed digestive biscuits and 75g melted butter and press into the base of a cake tin before placing in the fridge to firm up.
Next whisk together 700g ricotta, three eggs, 140ml double cream, 75g caster sugar, 3tbsp plain flour and the zest of an orange.
Carefully fold in 3tbsp banana skin puree, then pour over the biscuit base. Bake for one hour 25 minutes at 150c/300f. Allow to cool before removing from tin. Top banana!
MELON SEED SNACKS
“Just like sunflower and pumpkin seeds, melon seeds offer a concentrated source of useful nutrients,” says Dr Schenker.
“They are rich in minerals such as bone-building calcium and monounsaturated fats, which are important for heart health, plus dietary fibre.”
ALDO'S TIPS: Rinse and rub melon seeds in a fine sieve to remove all the flesh. Allow the seeds to dry on a clean tea towel and then toast them in a frying pan or roast them in a hot oven with a little spritz of oil.
Turn the seeds occasionally. When they are browned all over, sprinkle with a dash of salt.
Once cool, eat as a nutritious snack or sprinkle over salads for added crunch.
ONION SKIN STEW
The outer, papery skin on onions may be unpalatable, but it contains exceptionally high levels of protective antioxidants - much higher than the levels found in the onion itself.
“Onion skin is especially rich in a flavonoid called quercetin,” says Dr Schenker.
“This plant pigment has anti-oxidant and anti-inflammatory properties that some research suggests may help to reduce blood pressure and the formation of arterial plaque - the deposit that furs up arteries.”
ALDO'S TIPS: Use onion skin in stocks to add extra flavour. As quercetin is water soluble, you get all the health benefits too. Rip the onion skin into large pieces and gently simmer in stocks, soups and stews for extra flavour and colour.
Don't forget to fish out the onion skin before serving!
WATERMELON RIND SMOOTHIES
Researchers have found that the white area of watermelon rind between the green skin and pink flesh is rich in citrulline.
“This amino acid is recognised as being vital for the healthy dilation of blood vessels and circulation and plays an important role in removing toxins from the body,” says Dr Schenker.
ALDO'S TIPS: Use a vegetable peeler to remove the green skin from the rind, then put the white section in a blender with a squeeze of lime and plenty of chilled pink watermelon flesh.
Blitz everything together to make a nutritious smoothie that the whole family will love.
Another option is to slice the white rind thinly, then cook in a heavy based saucepan with several tablespoons of sugar and a knob of butter until the sugar starts to bubble, thicken and turn brown.
Make sure you don’t allow the sugar or fruit to burn.
Serve your sticky, sweet watermelon rinds with vanilla ice cream. Gorgeous!
LEMON PEEL ICE CUBES
Orange and lemon peels are high in fibre and contain far higher levels of antioxidants than the fruit itself.
In a recent study, the super-flavonoid antioxidants (protective nutrients that may help to significantly reduce cholesterol) taken from orange and tangerine peel were found to be 20 times more powerful than those found in the fruit's juice.
“It's well worth zesting oranges and lemons to get all the protective nutrients in their skins,” says Dr Schenker.
ALDO'S TIPS: I use citrus peel in a lot of my cooking. You can grate it over desserts and salads and add it to cakes and cocktails.
I also put large slices of citrus peel and butter under the skin when I roast a chicken. The oils in the peel bring out the flavour of the meat.
A few slices of lemon peel in a bottle of olive oil will flavour it beautifully. Citrus peels freeze well, too. Freeze large pieces and drop into drinks as a fancy alternative to ice cubes.
BROCCOLI LEAF PASTA TOPPING
According to Dr Schenker, broccoli leaves should never be thrown away. Their dark green colour indicates they are packed with vitamins and minerals, such as folate, iron and potassium.
In fact, research indicates 28g of broccoli leaves will provide 90 percent of your daily requirement of immune-boosting vitamin A, while an equivalent weight of florets provides just 3 percent.
ALDO'S TIPS: Cook the leaves quickly, as you would spinach. Blanch in boiling water, then fry with a little olive oil and garlic and add to pasta.
To get the best from broccoli stalks, make a salad by slicing off the tough outer peel and shaving what remains into ribbons with a potato peeler. Scatter with lemon zest, olive oil and Parmesan curls.
GINGER SKIN HOT TODDY
Everyone throws away the tough fibrous skin from fresh ginger, but it's worth rescuing it from the bin as it has health benefits.
“Ginger contains potent anti-inflammatory compounds called gingerols,” says Dr Schenker.
“These substances are believed to be the reason so many people with osteoarthritis or rheumatoid arthritis experience reductions in pain levels and improvements in their mobility when they consume ginger regularly.”
ALDO'S TIPS: You can add ginger peel to soup for flavour, but don't forget to remove it before eating.
The peel can be used to pep up fresh juices. Put a kiwi, banana, some spinach and a little ginger into a juicer - delicious!
Alternatively, steep ginger peel in boiling water for a few minutes to make an aromatic tea. I drink this as a tonic if I am feeling under the weather. It seems to help me recover more quickly.
PINEAPPLE CORE OVEN CRISPS
The tough skin and spiky leaves are inedible, but the fibrous core of this vitamin C-rich fruit is worth a place in your diet.
Pineapple core contains twice as much bromelain, an enzyme that can help to break down food during the digestive process, as the rest of the fruit.
It helps to prevent indigestion and research suggests it may have some anti-inflammatory effects.
“Though studies show mixed results, bromelain may reduce swelling, bruising, healing time and pain after surgery and injuries,” says Dr Schenker.
“It is often given to reduce inflammation tendonitis, sprains and strains. Studies of people having dental, nasal and foot surgeries found that taking bromelain reduced inflammation, too.”
ALDO'S TIPS: I often make tasty pineapple crisps from the core.
Just slice it thinly and place a single layer on baking parchment or a lightly oiled baking tray and dry in the oven on the lowest setting for around four hours.
Turn the slices over every hour or so to ensure even drying.
You should store your dried pineapple in an airtight jar and eat as a snack, sprinkled over porridge or as a decoration fors desserts and cakes. - Daily Mail
ALDO ZILLI is consultant chef of the San Carlo restaurant group