Michigan State University Extension
Preserving Food Safely - 01600512
10/13/97

### KEEPING FRUIT FROM DARKENING

     Some  fruits,  such as peaches, apples, pears and apricots

    darken
    when exposed to air and during freezing.   Directions

    for
     such   fruits   list antidarkening treatment as part of

    the
    freezing preparation.   Several  types of  antidarkening

    treatments
     are  used  because all fruits are not  protected

    equally
    well by all treatments.

     Ascorbic acid

     For most of the fruits that need antidarkening  treatment,

    ascorbic
     acid  (vitamin  C)  may  be  used.   This  is very

    effective
    in preserving color and flavor  of  fruit and adds

    nutritive
    value.

     Ascorbic  acid is available  at  drug  stores  in  various

    sized
    containers from 25 to 1,000 grams.  (Ascorbic acid may

    be
     obtained  also in  powdered form.)  One  teaspoon weighs

    about
     3 grams; thus  there  are  approximately  8 teaspoons

    of
     ascorbic acid in a 25-gram container.  In  the  recipes,

    amounts
     ascorbic acid are given  in teaspoons.

     Ascorbic  acid tablets can be used but are more  expensive

    and
     more  difficult to dissolve than the  crystalline form.

    Also
     filler in the tablets may make the syrup cloudy.   The

    amount
     of ascorbic acid in tablets is usually expressed  in

    milligrams.

     To use, dissolve ascorbic acid in a little cold water.  If

    using
    tablets, crush them so they will dissolve more easily.

     In  syrup  pack, add  the dissolved ascorbic acid  to  the

    cold
     syrup shortly before using.  Stir it in gently so  you

    won't
     stir  in air.  Solutions of ascorbic acid  should  be

    made
    up as needed.  Keep syrup in refrigerator until used.

     In sugar pack, sprinkle  the dissolved ascorbic acid  over

    the
    fruit just before adding sugar.

     In unsweetened pack, sprinkle the  dissolved ascorbic acid

    over
     the fruit and mix thoroughly just before packing.   If

    fruit
    is packed in water,  dissolve  ascorbic  acid  in  the

    water.

     In fruit juices, add ascorbic acid  directly to the juice.

    Stir
    only enough to dissolve the ascorbic acid.

     In  crushed  fruits   and  fruit  purees,  add   dissolved

    ascorbic
    acid to the fruit preparation and mix.

     Ascorbic  acid mixtures

     There  are   on   the   market    special   anti-darkening

    preparations--usually
     made  of  ascorbic  acid  mixed  with

    sugar
     or  with  sugar  and citric  acid.  If you use one of

    these,
     follow  the   manufacturer's  directions.   In these

    mixtures
     ascorbic  acid  is  usually  the  important active

    ingredient.
      Because of its dilution with other  materials,

    ascorbic
    acid purchased in these forms may be more expensive

    than
    the pure ascorbic acid.

     Citric  acid, lemon juice

     For  a  few  fruits,  citric  acid  or  lemon juice (which

    contains
     both  citric  acid  and  ascorbic  acid)  makes  a

    suitable
      antidarkening  agent.    However, neither  is  as

    effective
    as pure ascorbic acid.  Citric acid or lemon juice

    in
    large  quantities will  mask the natural fruit flavors or

    make
    the fruits too sour.

     Citric  acid  is  available  at  drugstores.   When  using

    citric
     acid,  dissolve  it  in  a little  cold water before

    adding
     to the fruit according to directions for that fruit.

     Steam

     For some fruits, steaming for a few minutes before packing

    is
     enough to  control  darkening.  Steaming  works best for

    fruits
    that will be cooked before use.

##### Go To Top of File &&&&&& MSU Extension Home Page &&&&&& Main Page for this Data Base

###### This information is for educational purposes only. References to commercial products or trade names does not imply endorsement by MSU Extension or bias against those not mentioned. This information becomes public property upon publication and may be printed verbatim with credit to MSU Extension. Reprinting cannot be used to endorse or advertise a commercial product or company. This file was generated from data base 01 on 03/09/98. Data base 01 was last revised on 10/13/97. For more information about this data base or its contents please contact wrublec@msue.msu.edu . Please read our disclaimer for important information about using our site.