Steps involved in canning of fruits and Vegetables

Steps involved in canning of fruits and Vegetables

Steps involved in canning of fruits and vegetables
1. Preparation of fruit and vegetables: Preparation of food commodity for canning consists of washing, sorting, grading, peeling, halving, blanching etc.

2. Raw material selection/receiving: For canning, fruits should be ripe but firm, evenly matured, free from blemishes, insect damage and malformation. Thus, harvesting at proper maturity is an important step in selection of raw material for canning.

  • Most fruits are harvested at soft ripe stage. However, apple, pear, peach and banana harvested at mature stage are preferred for canning.
  • Over ripe fruits yield poor quality product, while under ripe/immature fruit generally shrivel or toughen on canning.
  • Vegetables except peas, beans etc are harvested at mature stage to enable them to withstand cooking during sterilization.
  • Vegetables like green beans, green peas, ladies finger should be tender and free from soil, dirt etc.
  • Tomatoes should however, be firm, fully ripe and uniformly deep red in colour.

The specific requirements for canning of fruits and vegetables are given under Table 7.2 and 7.3.

Table 7.2 Specific requirement for canning of fruits

Fruits

Preparation

Syrup

Strength (oB)

Exhaust

Processing time at 100oC A2½ can) minutes

Type of can

Apricot

Use whole or halves, peel by dipping in boiling lye solution (2% NaOH) for 30 seconds to 1 minute, dip in cold water, cut two halves, remove pit, keep immersed in 2%salt solution until filled in can.

40 + 0.1 % citric acid

Exhaust can at 82-100oC for 6-10 minutes or until temperature in can center reaches 79oC.

20-25

Plain

Peach

Use whole fruit ,peel by dipping in boiling lye solution (2% (NaOH) for 30 seconds to 1 minute dip in cold water, cut two halves, remove pit, keep immersed in 2% salt solution until filled in can.

40

-do-

25

Plain

Banana

Peel, cut in to slices 12mm thick

30

-do-

25

plain

Grape fruit

Dip fruit in hot water at 93oC-96oC for 3-5 minutes, remove skin. Dip the peeled whole fruit in 2% hot lye, wash and separate the segments, fill segments in can.

60

Exhaust can at 82-87oC for 25-30 minutes or until temperature at center of can reaches 79oC.

30-40

Plain

Guava

Peel, cut into pieces, remove seeds and keep in 2% brine to prevent browning and fill in can.

40

-do-

20

plain

Litchi

Peel by hand, remove pits.

40+0.5% citric acid

-do-

25

plain

Pineapple

Peel, core and slice fruit, punch circular rings (5.6-8.8 cm diameter)

40

-do-

25

plain

Pear

Peel by hand, cut longitudinally into two halves, core and keep in 2% brine to prevent browning until filled in cans.

40+0.1%citric acid

-do-

20-25

plain

Jack fruit

Cut fruit into pieces, remove bulbs, separate seed from bulbs, use whole, halves or quarters.

50 + 0.5-0.75%

citric acid

-do-

20-25

plain

Loquat

Cut into halves

40

-do-

25

plain

Mango

Peel ,cut into slice, dip in 2% salt solution until filled in can.

40+0.3%citric acid

-do-

25

plain

Papaya

Peel, cut into slices, discard seed

45+ 0.5%

citric acid

-do-

25

plain





















































































Table 7.3 Specific requirement for canning of vegetables.


Vegetable

Preparation

Brine strength (%)

Exhaust

Processing

(A2½ can) at 121oC (0.7 kg/cm2 steam pressure)

Type of can

Asparagus

Wash, grade, cut lengthwise into pieces of desired size, blanch for 2-3 min.

2.25%

Exhaust can at 90-100oC for 7-10 minutes, (79oC in can center)

24

Plain /sulphur resistant

Beans

Use tender, stringless beans, slice 2.5cm length, blanch and fill in can.

2.25

-do-

40

Plain/ sulphur resistant

Cabbage

Shred cabbage, blanch in 1% citric acid boiling solution for 5-6 min, cool in 2% brine prevents discolouration fill in cans

2.0

-do-

40

Plain

Cauliflower

-do-

2

-do-

20

Plain

Carrot

Wash, scrape and blanch for 5-10 minutes in boiling water

2

-do-

25

Plain

Mushroom

Use tight buttons, blanch for 4-5 minutes, immerse in 2% salt solution, fill in cans.

2.0+ 0.3 % citric acid+ 1% sugar

-do-

25

Plain

Peas

Shell, grade, boil for 3-5 min

2+2.5% sugar

-do-

45

Sulphur resistant

Potato

Peel, keep in 2% brine, blanch in boiling water for 2-3 min, keep in 2.5% CaCl2 for 1 hour, wash and fill in cans.

2

-do-

45

Plain

Okra

Tender whole, blanch in boiling water for 1-2 minutes, cool in brine solution of 1-2% for 10 minutes, fill in can.

2 or in tomato sauce

-do-

35

Plain


Last modified: Wednesday, 7 March 2012, 5:09 AM