Bitter Apples For Cider Making - An Alternative

Experimental
Cultivar evaluations: Fruitlet samples were collected by cultivar. Some
were sub-sampled into “large” or “small” fruitlets to assess the relative influence
of size and date. Fruitlet samples were measured for average diameter, then
weighed. 100 - 200 grams of the fruitlets were then cut into small pieces before
grinding and mixing with a hand held “Bamix” unit. Grinding with, and without,
metabisulphite at circa 300 mg / kg was trialed. A sample of the ground pulp was
then placed in a disposable 10 mL syringe and approximately 2 mL of liquid
collected through a 0.45 um, 25 mm dia, cellulose acetate filter disc.
.
Total Polyphenol levels were measured using a standard Fosters method
(Costanzo, 2003) based on the ASBC and EBC International Method.
The juice samples were diluted 10 fold by volume with distilled water by
modifying the method and including 150 uL of sample instead of the usual 1500
uL, and increasing the distilled water to make up the same volume
The following aliquots were added to a disposable cuvette:
• 800 uL CMC / EDTA reagent
• 150 uL of sample
• 50 uL of Ferric Reagent (samples only)
• 50 uL Ammonia reagent
• 1450 uL of distilled water (use 1500 uL for blank)
After mixing and allowing a reaction time of 10 minutes, the absorbance
was measured against a reagent blank at 600 nm wavelength in a
spectrophotometer. Final result is calculated by multiplying corrected
absorbance at 600 nm x 547 x dilution factor to give results in mg/L.
Processing plant trials: A total of 185 tonnes of fruit thinnings were
collected over a period of 5-7 weeks from mid November until the end of
December. These were collected into waist belt held picking bags, before
consolidation into 0.4 tonne holding bins. The bins of fruitlets were hydro-cooled,
then stored in cool store at 4 degrees C until delivery to the processing plant on
the day of processing.
Fruit was processed on 6 Dec, 13 Dec, 21 Dec and 8-10 January. Milling
occurred using a Rietz mill (10 mm screen) with addition of sodium
metabisulphite solution at milling to give a level of approximately 300 mg/kg
SO2. Some additional water was also added at milling to facilitate pumping to
the mash holding tanks. Pectolytic mash enzyme was added at a rate of
approximately 300 mL/Tonne, before holding for 1 – 2 hours at 20 – 25 degrees
C. Juice was extracted using a Bucher HPX5005i fruit press, then flash
pasteurised into agitated fining tanks where fining agents silica sol and bentonite
were applied. The juice was then cross-flow filtered in a Bucher “Ministar –metal”
unit employing Graver technologies filter elements having 0.1 micron pore size
titanium oxide membranes supported on 316 sintered stainless steel. Finally, the
juice was concentrated in an APV rising / falling film plate evaporator to around