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Process manual for Vegetable Crackers

This article provides the complete information required to make vegetable crackers. The following notes introduce the main sections of the document.


In all cases at least two recipes have been given. The first is a standard proven recipe used in the industry, which can be developed to meet particular requirements in taste or texture for the target market. The second recipe is an actual recipe from a leading producer for a leading product brand.

Critical ingredients 

Following each recipe some notes have been added to identify any particularly important ingredients for the product.


The process descriptions are based on the best practice for producing a high quality product. The process may be modified to suit the equipment available. For each product, recommendations are made with regard to the type of equipment required for the mixing process, baking, in particular the power required and the recommended baking band. Modifications to the recipes and process recommendations may be required to suit the equipment available.

Ingredient specifications 

Some notes are given under this section of the report to identify the most important and special ingredients required.

Production machines: specifications 

This section lists the key features of the production machinery to achieve the optimum product quality and output. In some cases the specifications may vary from the actual equipment available. In these cases, discussions and development work during the trials will need to be carried out to achieve the best possible product quality.



Very light and delicate texture snack crackers with vegetable flakes and oil sprayed to give an aromatic flavour. These crackers are usually modified with proteolytic enzyme and aerated with ammonium bicarbonate and sodium bicarbonate.

Product specification

Dimensions:                48 x 48mm
Thickness:                   4.4 mm
Weight:                         3.75 g
Appearance:                Evenly blistered
Colour:                         Golden with vegetable flakes
Texture:                        Light and delicate with soft mouth-feel
Flavour:                        Aromatic flavour
PH:                                5.5
Moisture:                     2.5%


  1. Flowpack with stack of 6 biscuits, packed in cartons.
  2. Biscuits on edge in trays and wrapped in Flowpack.

Production output 

Oven cutting machine width 1250 mm
No. of crackers across the band: 21
Baking time: 5.0 mins
Biscuits per min. 21 x 965 = 20265/5 = 4053
Kg per hour: 4053 x 60 x 3.75/1000 = 912
Output at 90% efficiency: 820 kg/hr

Baking time: 4.0 min
Biscuits per min. 21 x 965 = 20265/4 = 5066
Kg per hour: 5066 x 60 x 3.75/1000 = 1140
Output at 90% efficiency: 1025kg/hr

Nutritional data

Vegetable cracker (1)     Ingredient nutritional values in mix (1)
Recipe Weight (kgs) Moisture content and loss during baking % Dry weight Carbohydrate Protein Fat Energy kcal
Wheat flour 100.00 14.0 86.00 77700.0 9400.0 1300.0 350000
Fat 13.54 0.0 13.54 0.0 0.0 13540.0 121860
Malt extract 2.08 20.0 1.66 1460.0 94.0 2.0 6052
Invert syrup 1.04 23.0 0.80 759.0 0.0 0.0 3078
Salt 1.23 0.0 1.23 0.0 0.0 0.0 0
Ammonium bicarbonate 2.60 10.0 0.00 0.0 0.0 0.0 0
Sodium bicarbonate 0.44 50.0 0.22 0.0 0.0 0.0 0
ACP 0.05 0.0 0.05 0.0 0.0 0.0 0
P. enzyme 0.18 0.0 0.18 0.0 0.0 0.0 0
Vegetable flakes 2.00 12.0 1.80 0.0 0.0 0.0 0
Water 25.00 100.0 0.00 0.0 0.0 0.0 0
Totals       79919.0 9494.0 14842.0 480990
Total weight of mix 148.16            
Total dry weight     105.48        
Final moisture content   3.0          
Yield of biscuits 108.74            
Nutritional values of vegetable crackers per 100gm          
Energy (kcal) 442.30            
Protein (gm) 8.70            
Carbohydrate (gm) 73.50            
Fat (gm) 13.60            
(1) calculated from table of McCance and Widdowson 1991        


Savoury crackers are mixed on horizontal mixers and the dough is stood to allow the action of the protoelytic enzyme on the gluten. Forming is by sheeting and cutting. Baking is on a Z47 type wire-mesh band. The crackers are oil sprayed immediately after baking.

Formulation   (1)   (2)
  with enzyme   with SMS
Flour (weak)  100.00 90.00
Cornflour 10.00
Powdered sugar 3.00
Invert syrup 70%   1.04 16.0
Malt extract 80%  2.08
Dough fat 13.54 14.0
Lecithin  0.28
Ammonium bicarbonate 2.60 3.00
Sodium bicarbonate 0.44 1.00
Acid calcium phosphate 0.05
Salt 1.23 1.00
SMS 0.05
Proteolytic enzyme 0.18
Dehydrated vegetable flakes 2.00 2.00
Water 25.0 25.0

Critical ingredients

  1. Flour should be weak with a protein content of 8-9%.
  2. Proteolytic enzyme (proteinase).
  3. Oil for spraying: coconut oil or palm kernel oil are suitable and have a good resistance to rancidity.

Alternative formulations 
Similar products can be made using SMS (sodium metabisulphite) in place of the proteolytic enzyme. The SMS increases the extensibility of the gluten and does not require the 3 hour standing time.



An “all in” mix on a horizontal mixer
Temperature of final mix about 33°C for enzyme doughs
Temperature of final mix about 40°C for SMS doughs.
The vegetable flakes may be mixed into the dough.

Standing time 

After mixing the dough is stood to allow the enzyme to react with the gluten. The standing time is about 3 hours at 35°C. The time must be determined carefully depending on the amount of enzyme and the quality of the flour in order to achieve the soft, delicate eating texture of the cracker.
Doughs made with SMS do not require a standing time.


The dough is sheeted, gauged and cut, (laminating is not required).

Typical roll gap settings are:

Sheeter:                      12mm
Gauge roll 1:              6
Gauge roll 2:              3
Gauge roll 3:              1.5

If the vegetable flakes are to be sprinkled, a suitable sprinkler unit before the final gauge roll is required.


Baking time:  4.0 – 5.0 mins.
Temperatures: 220 / 220 / 210 / 180
High bottom heat in Zones 1 and 2 is required

Baking band 
Z47 type wire-mesh band
Pre-heat is required

Oil Spray 
The oil spray should be located immediately after the oven. An application of 10 – 16% by weight of coconut oil is recommended.

Production machines:


Horizontal 2 speed (30/60 rpm) or variable speed mixer
75 KW motor

Baker Perkins high speed horizontal mixer
Baker Perkins high speed horizontal mixer


DSM Dingson Food Machinery forming line
DSM Dingson Food Machinery forming line 

3 roll sheeter with good scrap incorporation
3 pairs of gauge rolls (final rolls 400 mm diam.)
Rotary cutter (single roll or two roll system)
Vegetable flake sprinkler positioned before the final gauge roll unit

Direct gas Fired Oven
Z47 type wire-mesh band
Average oven burner rating 28 KW/m2

Baking temperatures: 220 / 220 / 220 /180°C
Baking time: 4.0 – 5.0 minutes 

Ingredient specifications:


The flour shall be milled from good quality soft wheat, free from infestation and impurities, especially pesticides. The flour shall not be treated with enzymes and shall not contain chemical additives. The appearance shall be a good white colour, free from bran particles. The odour shall be free from mustiness and foreign odours.

Two flours are required, described in the recipes as strong and weak. An analysis of each is given below.

  Weak flour Strong flour
Semi-sweet doughs Fermented doughs
Starch 74.5 71.5
Moisture 14.0 13.5
Proteins (gluten forming) 7.0 10.0
Proteins (soluble) 1.0 1.0
Sugar 2.0 2.5
Fat 1.0 1.0
Ash (mineral salts) 0.5 0.5
Total 100.0 100.0


The sugar shall be free from impurities and infestation. The appearance shall be a fine, white crystalline solid, free flowing and free from lumps.

The sugar shall have a sweet taste and be free from odours.

Moisture content:      0.06% maximum
Ash content:               0.03% maximum
Particle size:
Caster sugar:  MA = 276 to 300 um  CV = 16 to 26%
Icing sugar:                 Maximum held on a 100 um sieve 6%
                                       Maximum held on a 60um sieve 13%
                                       Tricalcium phosphate may be added to 1.5% max. 
MA      Mean aperture
CV       Coefficient of Variation

Cane syrup 80% 

Syrups with 80% solids derived from the refining of cane sugar. Used for their excellent flavour.

Invert syrup 70% 

Syrup of 70% solids made by acid hydrolysis of sucrose. The result is a 50:50 mixture of dextrose and fructose which are both reducing sugars and contribute to the maillard reaction in baking.

Malt extract 80% 

A thick glutinous syrup of 80% solids usually non-diastatic and obtained by water extraction of malted wheat or barley. The heat treatment used to concentrate the solution destroys any enzymes. Used as an important flavour ingredient. Rich in maltose, which is a reducing sugar.

Dough fat 

The fat shall be free from impurities and appear clean and bright when melted. The fat should be odourless, free from rancid and foreign flavours. The fat should be produced from good quality crude oils by a process of refining, bleaching and deodorising. It should be made primarily from vegetable oils, but it may contain hydrogenated fish oils.

Free fatty acid (as oleic acid)                            maximum 0.08 %
Peroxide value (milli equivalent per kg)        maximum 1.0
Moisture                                                               maximum 0.1%
Slip melting point (BS 684 1.3 1976) 34 to 37°C.

Coconut oil 

For use in oil spray.
Hydrogenated coconut oil, neutralised, deodorised and bleached.
Melting point: 32 to 34°C


A complex natural surfactant obtained from soya beans

Ammonium bicarbonate (“Vol”) (NH4)HCO3         

A volatile salt, which, when heated liberates carbon dioxide, ammonia gas and water.

                                                                        Min.                Max.

Ammonium bicarbonate                           99.0%
Heavy lead                                                     0                     10ppm
Arsenic                                                            0                     1ppm
Basic magnesium carbonate                       0.5                  1.0

Sodium bicarbonate 

The most important aerating agent. When heated it liberates carbon dioxide and water, leaving sodium carbonate as the residual salt. Sodium carbonate has a softening action on gluten and darkens the biscuit.If sodium bicarbonate is heated, only half the carbon dioxide is released, but if an acid is present all the carbon dioxide is released and there is no softening action on the gluten or darkening of the colour of the biscuit.

ACP – Acid calcium phosphate 

Acid calcium phosphate is also known as monocalcium phosphate. It is fairly soluble in cold water, but for doughs which are used without standing, a good proportion of the reaction takes place during baking. It is used in conjunction with sodium bicarbonate and ammonium carbonate.


Sodium chloride, used as a flavour enhancer and also to control the rate and extent of fermentation.

SMS – Sodium metabisulphite Na2S2O5 

A reducing agent for the modification of the strength of the gluten in doughs

Proteolytic enzyme (proteinase) 

Used to soften the gluten in doughs. A white, fine powder. 

Production machine requirements:


High speed horizontal dough mixer

  • 850 kg batch capacity
  • tilting bowl (150 degree tilt)
  • variable speed drive 75 KW
  • water jacket with chilled water supply
  • shaftless blade
  • two – dry ingredient feed inlets
  • four – liquid ingredient ports
  • four – dough tubs (additional dough tubs will be required for fermentation)


Vertical spindle mixer

Thomas L Green 3 spindle mixer 
Thomas L Green 3 spindle mixer – Reading Bakery Systems 
  • Capacity 800 kg
  • three spindle mixing paddles
  • mobile mixing bowls
  • single speed drive (25 rpm)

Dough feed system

  • tub tilt and tipping unit
  • bulk feed dough hopper with dough breaker
  • 2 roll dough feeder
  • dough conveyors with metal detector and reject system
  • dough shredder for rotary moulded doughs


  • Vertical laminator
    Hopper with scrap incorporation
    3 roll sheeter
    Dough sheet conveyor
    Two gauge roll units with cartridge conveyors
    Dough sheet layering unit with cut sheet facility
    Fat/flour spreader
    inclined conveyor to feed first gauge roll unit

  • 3 roll sheeter with hopper and scrap incorporation (420mm diam. top rolls)
  • currant spreader
  • 3 pairs of gauge roll units with bottom roll adjustment (2 units 300 mm diam., and one unit with 400 mm diam. rolls)
  • vegetable flake sprinkler
  • seed sprinklers
  • flour sprinklers
  • intermediate web
  • rotary cutting web (endless cotton belt)
  • rotary cutter (4 roll type)
  • separate cutting ad embossing rolls
  • scrap lift, cross conveyor and scrap return conveyor
  • cross conveyor for side crap
  • side scrap wheels
  • scrap dough distributor over the sheeter of the laminator
  • decorating conveyor
  • salt sprinker with recovery system
  • swivel panner with guide rollers for oven band and automatic band tracking


Baker Perkins rotary cutting line
Baker Perkins rotary cutting line

Control system and components

  • inverter variable speed drives
  • cascade control
  • adjustable roll gaps by handwheels with indicators
  • roll scraper position adjustable on each gauge roll
  • manual web tracking controls
  • automatic web tension
  • PU synthetic webs
  • endless cotton cutting web


Baker Pacific DGF cracker oven
Baker Pacific DGF cracker oven

Baking oven

  • 1.0 m wide x 56 m long
  • Direct Gas Fired Oven
  • burner rating of 30 KW per sq.m of oven band
  • oven band pre-heat system
  • high rate burners in first zone
  • 5 temperature control zones
  • automatic temperature control system
  • top and bottom heat control
  • 5 extraction flues with fans and damper controls
  • pneumatic band tension system
  • Z47 type baking band
  • alternative CB5 baking band (specification page 105)
  • variable speed oven drive
  • baking time from 3 – 8 minutes
  • automatic band tracking system
  • emergency wind out system
  • wire-mesh take off conveyor with retractable nosepiece
  • cross conveyor for reject
  • safety systems
  • oven band cleaner
  • cracker breaker


 Dingson Food machinery DSM oil spray
Dingson Food machinery DSM oil spray

Oil Spray

  • stainless steel oil spray machine
  • drain conveyor 2.0m long
  • spinning disc type with adjustable masks
  • filter system
  • mist collection system
  • oil collection sump (removable for cleaning)
  • oil circulation pump

Cooling system

  • 1:1.5 baking to cooling ratio (1:2 baking to cooling ratio recommended for sultana biscuit)
  • two tier cooling system 90m long
  • automatic band tracking
  • automatic band tension
  • PU Synthetic webs
  • all webs with scrapers and catch trays
  • biscuit stacking machine with by-pass for cracker strips
  • predictor controlled channelling board
  • adjustable star wheel
  • cracker breaker on packing table
  • packing table with stainless guides

Quality control

The following is a checklist of the important quality control requirements. Most of these will be standard for all the products made in the factory.

Raw materials

Moisture content
Gluten content (Kjedahl)
Detection of flour treatment

Fats and Oils 
Acid value
Kreis test for rancidity
Slip melting point 


Ingredient weights
Feeding sequence and timing
Mixing time
Dough consistency

Dough volume

Dough sheet thickness (after sheeting and gauge rolls)
Dough piece weights (across the band and with time)
Dough piece dimensions
Dough piece form

Moisture content
Biscuit weight
Biscuit dimensions

Oil spray 
Oil weight (across the band and with time)

Metal detection
Number of biscuits in pack
Pack weights (minimum / average / maximum)
Date codes


Baker Pacific Ltd. have used several reliable sources for the information provided in this document. However, Baker Pacific Ltd does not accept liability for any omissions, errors either of content or interpretation.  Baker Pacific Ltd does not accept liability or responsibility for any consequences whatsoever arising from the use of information contained in this document.

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