Assessing Quality

Passionfruit is typically sold based on a combination of fruit size and amount of external blemish present.

Size

  • Passionfruit has been approved by the National Measurement Institute for sale by the piece instead of by weight
  • The standard industry sized box is the T35 carton – 375mm (L) x 280mm (W) x 188mm (H) – and accommodating between 5-9kg in weight depending on the passionfruit variety
  • The T35 fits 12 units per layer on a standard pallet and is typically a 2 piece item – with a separate box base and lid
  • Fruit counts in the box form the basis for the sizing of passionfruit – Size 90 means 90 pieces of fruit in the box and Size 140 means 140 pieces – meaning the larger the number, the smaller the fruit size
  • At the retailer, the fruit is most often sold for a piece price e.g. $1.20 per piece
  • The most popular sizes for retail sale in purple varieties are 100 – 120 units per box, as this represents the best value for both retailer and consumer for individual piece sales
  • Smaller fruit is typically packed into multi-unit formats like string bags and sold for a discounted price
  • The larger Panama style passionfruit are sometimes sold as pattern packed trays where the presentation of the fruit is excellent

Skin Quality

  • Fruit is graded into Class 1 and Class 2 fruit with Class 1 commanding a price premium
  • In some markets, there is an ultra-premium grade sold to a very limited number of customers.   This fruit is large, heavy for its size with an unblemished exterior and intense, sweet juicy flavour
  • Many disease and pest issues can affect the exterior quality of a passionfruit
  • The industry has a grading guide available to assist with correctly grading fruit for sale to the wholesale markets
  • Request a copy of the Grading Guide Poster here

Current Fresh Market Specifications

Purple varieties like Misty Gem, Sweetheart and Flamenco

Panama varieties like Pandora, Lakeland and McGuffies Red

Assessing Taste

At the end of the day, it doesn’t matter how big the fruit or how perfect the skin if the passionfruit doesn’t taste good.  Testing the eating quality of your fruit should be a critical part of your Quality Assurance program.

How can you assess the flavour?

  • Taste-test your fruit on a regular basis so you can assess how the flavour and sweetness changes over time
  • Taste fruit from different parts of your orchard side by side so you can determine any major flavour differences which can highlight a nutrition shortfall in parts of your orchard
  • Use a refactometer to objectively assess the Brix or dissolved solids in your fruit

Where can you buy a refractometer?

  • The simplest option is to buy one online from a mass retail site like eBay or Amazon
  • Your farm supplies retailer may also be able to provide one, although this is likely to be a more expensive model than those found online

How does a refractometer work?

  • When light enters a liquid it changes direction; this is called refraction
  • Refractometers measure the degree to which the light changes direction, called the angle of refraction
  • A refractometer takes the refraction angles and correlates them to refractive index (nD) values that have been established
  • Using these values, you can determine the concentrations of solutions. For example, solutions have different refractive indexes depending on their concentration
  • The prism in the refractometer has a greater refractive index than the solution
  • Measurements are read at the point where the prism and solution meet
  • The % Brix Scale shows the concentration percentage of the soluble solids content of a sample (water solution)
  • The Brix scale is calibrated to the number of grams of cane sugar contained in 100 g of water
  • When measuring a sugar solution, the % Brix reading should perfectly match the actual concentration

How to use a refractometer

Apply a couple of drops of the passionfruit juice onto the clean, dry lens surface.  Add enough juice to cover the lens when the cover is closed.

Close the flap and hold the refractometer up to your eye facing a light source

The reading should show you the % Brix in the juice.  Ensure you clean the prism lens thoroughly between samples and use a soft cloth to avoid scratching the lens.

Make sure you have calibrated your refractometer prior to use.  Watch this video for a simple process of calibration.

Ideal Brix range for fresh Passionfruit?

12-18% sugar is ideal to deliver the sweet flavour. 

Remember that sweetness will continue to develop after the fruit has been picked so on-farm readings may be closer to the 12% level, but still deliver 15+ readings after a few days transit to the market floor.