3.17 Sauces

PROCESS	NOTES
Sliced vegetables/fruits	Prepare vegetables as shown in Diagram 3.13 and fruits as shown in Diagram 3.1.
Pulp	Prepare a pulp from raw/cooked vegetables manually or using small pulping machines (Figs. 4-6).
Mix ¬ salt Mix ¬ water Mix ¬ sugar	Prepare a brine containing some or all of the ingredients according to the formulation for the product required and to taste (e.g. in the choice of spices, amount of sugar etc.).
Heat ¬ vinegar Heat ¬ spices	Heat to 80-90° C with constant stirring. Add vinegar at end of heating to give final concentration of 2-6% salt and 6-10% acetic acid.
Fill/seal ¬ bottles/jars + lids	Jars and lids sterilised by boiling in water for minimum of 10 min. Hot fill sauce into bottles or jars while jars are hot to prevent breakage. Small lid sealers available (Fig. 11). Simple bottle capping machines are available (Fig. 15).
Cool	Cool in air or more rapidly in a jar cooler (Fig. 8).

ADDITIONAL PROCESSING NOTES

Cutting to Pieces of Food and Pulping

Chopping, de-stoning, slicing, dicing and grating form large to medium sized pieces. The purpose is to make food more uniform and more attractive, to allow uniform heat penetration or drying rates, and even mixing. Pulping can be done by hand, by a fruit press, a fruit mill or hand pulper/siever. All metal in contact with the fruit should ideally be stainless steel. Some fruits are heated before pulping to give a higher juice yield and to stop browning.

Salt and Sugar

These have similar actions at high concentrations (16% salt and 65% sugar) in preventing microorganisms from growing. The high concentration preserves the food by both drawing out water from the food and in the case of salt, by its anti-microbial properties and interference with the action of enzymes.

Acid and Alcohol

The natural acids of fruits help in preservation of jams, juices etc., and vegetables may be acidified by adding vinegar or fermenting to produce lactic acid and make pickles. The amount of sugar added to acidic foods such as jams or pickles, is found by the following formula:

% sugar = 80 - (20 x % acid present)
when the acid is measured as acetic acid.

For example, if the food has 2% acetic acid, 40% sugar should be added to adequately preserve the food. Advice on the measurement of acid concentration should be sought when starting production, but once found, the result can be used routinely without further technical advice.

In the fermentation of wines and beers it is important to use yeasts that are specifically bred for alcohol production and not rely on natural contaminating yeasts which may produce acids and give variable product quality and high losses through spoilage. An example of natural fermentation is palm wine where the shelf life does not exceed 12 hours due to contaminating micro-organisms which produce acid.

Other important factors include the acidity of the fruit which may have to be adjusted to give good fermentation by the yeast, and yeast nutrient which helps the yeast to grow rapidly and therefore produce a rapid fermentation. After the fermentation the yeast settles out and is removed. This should produce a clear drink, with no flavour of the yeast, but additional clarification is often necessary with many fruit juices and pulps used in winemaking. Great attention must be paid to hygienic conditions to stop the growth of unwanted micro-organisms. Sterilising chemicals (e.g. sodium metablsulphite or Camden tablets) and/or boiling water are essential to sterilise all processing equipment. Sulphur dioxide can be tasted at concentrations above 500 ppm (mg/kg) and all traces should therefore be removed from equipment to avoid contamination of the products.

QUALITY CONTROL

Hygiene

Large quantities of water are often used in fruit and vegetable processing and water quality is a key factor in overall product quality. Well water is often contaminated and a variety of water filters are available to purify it. However, these are often slow and an alternative solution is to chlorinate water. This can be done by adding one teaspoonful of bleach per gallon of water. It is strongly recommended that expert advice is sought on the suitability of available water in a particular area.

Strict hygiene should be observed at all times during processing. Clean aprons or overalls should be worn. Gloves should be used when preparing fruit as the acid, and in some cases, enzymes (for example, in pineapple) can damage the skin. Good water quality and hygienic conditions are needed to prevent recontamination of the food. Surfaces should be made from metal, stone or plastic covered wood to allow proper cleaning, and all utensils should be thoroughly cleaned after use.

Stainless steel knives and plastic or wooden utensils should be used for fruit because they do not react with the acids in fruit (wooden utensils, including cutting boards, are more easily cleaned than wooden tables. Wooden utensils can therefore be used, but not wooden tables). Copper, iron and brass should not be used because they produce off-flavours in the food.

In the production room floors should be sloping concrete for proper cleaning and drainage. Walls should be smooth for cleaning and there should be no ledges or rafters which could collect dust, bird droppings etc. Windows and doors should be netted to reduce insect contamination of the product During processing, the workers should wash their hands, wear clean overalls and not smoke. All work surfaces should be cleaned after each days production. If a worker is ill, especially with a stomach complaint, he/she should not be allowed to work that day. Local public health regulations should be understood and followed. This is especially important in vegetable processing where the low acidity of the product increases the risk of transmitting food poisoning bacteria to the food.

Quality control is used to make sure that the quality of food is the same for every batch each day. This is important because when customers buy food they expect it to be the same as the last time. If it is not, they will loose confidence in the product and stop buying it. Quality control is also useful to control production costs and identify parts of the process that are too expensive. Quality control is also needed to ensure that the food meets local legal limits (for example the % fruit in jam, the amount and type of preservatives, the weight of food in a jar or bottle and local labelling laws). Details of these laws should be found out before production starts.

Raw Material Control

All raw materials should be harvested when fully mature but (except for fruit that is to be pulped) not over-ripe. The appearance of the skin, fruit hardness, and colour can be examined during sorting/grading in a small scale enterprise. Taste can be assessed by the ripeness (colour, odour, size and hardness). Information about the internal condition of the fruit can be found by the presence of surface defects such as scabs and blight.

Raw materials should be clean, free of mould/yeast/bacterial contamination, insect damage and without serious bruising, splitting etc. Skin defects are less serious if the fruit or vegetable is to be peeled, but these may also indicate more serious internal damage. A summary of the factors to examine in the control of raw material quality are summarised in Table 2.

Table 2: Quality Control Factors for Raw Material Control

Product	Size	Shape	Colour	Maturity	Skin Blemish	Insect/Microbial Damage
All fruit drinks			·	·		·
Fruit in syrup	·	·	·	·		·
Preserves	some		·	·	some	·
Dry salt/pickles	some	some	·	·	some	·
Sauces		·	·		·

Process Control

Raw materials should be carefully washed to prevent soils, insects etc. from contaminating the final product, and sorted/peeled to remove unwanted parts of the plant. The main process control points for the products in this chapter are shown in Table 3.

Table 3: Process Control Points

Product	Weight of Ingredients	Heating Time & Temperature	Sugar Conc'n*	Acid Conc'n*	Salt Conc'n*	Alcohol Conc'n*
Juice		·
Squash	·	·	·
Cordial	·	·	·
Nectar	·	·	·
Syrup			·
Wine	·	·				·
Spirits	·	·				·
Vinegar	·	·		·
Fruit in syrup	·	·	·
Preserves	·				·	·
Dry salt vegetables
Brined vegetables	·	·		·	·
Pickles	·	·	·	·	·
Sauces	·	·	·	·	·
QUALITY CONTROL EQUIPMENT	Scales	Thermometer	Refract -ometer	Ph meter**	Hydrometer

(Fig. 9)

* Conc'n = concentration

** Salt meters are available but unlikely to justify the relatively high cost. Technical advice on salt determination by titration should be sought.

Product Control

All products are assessed by one or more of the following criteria: texture/consistency, colour, flavour/taste, odour. Consumer studies should be undertaken to find the most acceptable product formulations. Raw material and process control should then be used to ensure that quality is reproduced in every batch.

PACKAGING AND STORAGE

Each of the products described is suitable for packing into glass containers. The main quality control procedures are to ensure that there is a correct fill weight (as displayed on the label) and to ensure that the containers are safe (free from glass splinters, cracks and soils) and that they are properly sealed. Most products, if they are properly processed, should have a shelf life in excess of 6 months and up to a year if stored in cool dark conditions.

Packaging

There is a general problem in packaging foods at a small scale. Packaging is expensive, may not be available on a regular basis and may form the largest single production cost. The main types that are used for fruit and vegetable products are: glass or plastic containers, or plastic bags.

Glass

The advantages of glass are that it is smooth, hygienic, easily cleaned, reusable (with new lids) and stackable. It also gives a better appearance to the product which increases customer acceptability and makes the food more valuable. The disadvantages are that it is breakable, expensive and heavy (therefore causing high transport costs). If the containers are reused care should be taken to make sure that they are thoroughly cleaned by washing in soapy water and rinsing in clean water. Bottle washers are available (Figs. 13-14). The containers should be sterilised with hot water, or steam. Do not place them directly into boiling water as they will break. They should be heated slowly to boiling and held at that temperature for at least 10 minutes. Bottles can be cooled in a continuous cooler (Fig. 8) when they contain juices, pickles or sauces. Jams must be stationary when they cool to allow the gel to form.

Plastic Bottles and Jars

These are available in some places and are cheaper than glass. However, they are not reuseable and form a poorer seal. This can lead to insect contamination, or in pickles to loss of acetic acid vapour, and hence a shorter shelf life. They should be washed with hot water, but the container is unable to withstand boiling temperatures. The product is therefore difficult to hot fill and may need preservatives to give the required shelf life.

Plastic Film

This is suitable for sachets or small packages of sauces, jams and chutneys. The plastic does not protect the food as well as the solid containers and the product therefore has a shorter shelf life.

Sealing

Simple hand sealers are available for jars and bottles (Figs. 11 & 15). Films can be sealed by an electric sealer or by a candle flame when the film is folded over a hacksaw blade.

Equipment

Fruit and Vegetable

· Water filter (Fig. 2)
· Peeling equipment (Fig. 3)
· Pulping equipment (Fig. 4-7)
· Sealing machines (Figs. 11-15)
· Bottle/jar cooler (Fig. 8)
· Refractometer (Fig. 9)
· Hydrometer
· Fermenter and air lock (Fig. 10)

Further Reading

Adams, M.R. (1980)	Small Scale Production of Vinegar from Bananas. TDRI Post Harvest Technology Publication, G132 56/62 Grays Inn Road, London, UK
Bielig, H.J. (1973)	Fruit Juice Processing FAO Agricultural Services Bulletin 13, FAO, Rome.
Finstead R., Devey,	Pickle and Sauce Making Food Trade Press Ltd. London, UK
J.D. & Dakin, J.C. (1971)
Fernandez, R., Cooke R.D., Quiros, R., Madrigal, L., Samuals, A. Aguilar, F., & Orfiz, A. (1980)	Fruit and Vegetable Processing and Appropriate Technology in Costa Rica; A Case Study. Tropical Science, 1980. 22 (2)
Mabey, D. & R. (1985)	Jams, Pickles and Chutneys Harmondsworth, UK (Penguin Publ)
Min. of Agriculture and Food (1969)	Home Preservation of Fruit and Vegetables Bulletin 21, Fisheries Her Majesty's Stationery Office, 49 High Holborn, London WC1
Rauch, G.H. (1965)	Jam Manufacture Leonard Hills Books, London
Turner, B.C. (1970)	Home Wine Making and Brewing Boots Company Ltd., London
US Department of Agriculture	Preservation of Vegetables by Salting or Brining. Farmers Bulletin, No. 1932.
FAO	Rural Home Economic Food Preparation, Series 1 Food Presearvation, Series 2 Labour Saving Ideas, Series 3 FAO, Via delle Terme di Caracalla, 00100 Rome, Italy.
Ihekoronye, A.I, and Ngoddy, P.O. (1985)	Integrated Food Science and Technology for the Tropics. Macmillan Publishers. London. UK
International Women's Tribune Centre (1984)	Women and Small Business International Women's Tribune Centre, 777 UN Piaza, New York, NY 10017, USA.
Jackelen, H.R. (1983)	Management for Commercial Analysis of Small Scale Projects. AT International, 1724 Massachusetts Avenue, N.W. Washington, DC20036, USA.
ILO-SDSR	Makala Ya Mafunzo. (Catalogue of Items of Appropriate Technology) Skill Development for Self Reliance. ILO/SDSE, PO Box 60598. Nairobi, Kenya.
VITA (1970)	Village Technology Handbook VITA College Campus, Schenectady, New York 12308, USA.

Figure 1 BOXES FOR HARVESTING

Figure 2 BLEACHING

USE CLEAN CHLORINATED WATER.
WASH YOUR HANDS.
WEAR A CLEAN APRON OR COAT.
WEAR GLOVES.
USE METAL, STONE OR PLASTIC TABLE SURFACES
INSTEAD OF WOOD.

Figure 3 PEELING MACHINE

Figure 4 FRUIT PRESS

Figure 5 FRUIT PRESS

Figure 6 FRUIT PRESS

Figure 7 PULP PRESS

Figure 8 BOTTLE COOLER

Figure 9 REFRACTOMETER

Figure 10 AIRLOCK

Figure 11 JAR SEALER

Figure 12 FERMENTATION OF VEGETABLES

Figure 13 BOTTLE WASHERS

Figure 14 BOTTLE WASHERS

Figure 15 BOTTLE SEALER