Etiket Arşivleri: FE475

Food Quality Control Lab. – Meat & Meat Products ( Emrah ÇETİN )

Purpose :

Our purpose is analysing the meat and meat products and their quality parameters which are determination of total fat content as percent value, the moisture content, pH values, and off-odour of the products from şahin( sucuk), pınar(sausage), maret(sausage), pınar(salami), and banet(sucuk).

Theory  :

THE COMPOSITION OF MEAT:

Water

Water content can be decreased (e.g. dried or dehydrated meat), and it varies in many processed meats such as sausages, salamis, bacon and ham. During these processes, care must be taken to protect the nutritional and organoleptic (taste, smell, texture and appearance) properties of the meat.

Protein: Protein is the source of the essential amino acids necessary for life. It is the building block of the muscular tissue.

Fat: Fat itself consists of triglycerides (see below), and is the main energy reserve for the animal. Other important substances (e.g. some vitamins) are dissolved in this fat.

Soluble non-protein organic substances: These substances fall into two categories: nitrogen-based substances such as free amino acids and vitamins, and carbohydrates such as lactic acid and glucose.

Inorganic substances: The major minerals consist of phosphorous and potassium together with small amounts of sodium, magnesium, calcium, zinc, and other trace metals.

  • Addition of reducing sugars (e.g. glucose solids, dextrose) to the brine also helps in browning reactions during thermal processing to produce a desirable colour and a caramel flavour in some products such as bacon.

  • 1–2%, are added to the brine during various commercial operations in order to lower the water activity of meat during curing.

Enhancing the texture and sensory quality of high pressure treatment meat products

Although many in the food industry perceive high pressure treatment as a relatively new technology, early investigations examined the ability of high pressures to increase the shelf-life of milk treated at ambient temperatures. Since then, the effect of high pressure on micro-organisms, proteins and, more recently, in food processing has been studied. Work at The National Food Centre investigated the use of high pressure (150 MegaPascals – MPa) to enhance the functionality and acceptability of frankfurters with reduced salt and phosphate concentrations, and breakfast sausages with reduced phosphate, in an effort to address consumer demands for high quality products with fewer added ingredients.

Sodium chloride (salt) and phosphate are essential ingredients in meat processing, where they act by solubilising the myofibrillar proteins that contribute to water-holding capacity, thus reducing cook loss. These ingredients also enhance fat binding in meat products, entrapping other ingredients to form a uniform and cohesive mass. Salt also decreases water activity, which significantly extends the shelf-life of the product. However, consumption of excess sodium chloride has become a major issue in the food industry because of the relationship between sodium and hyper-tension in humans. According to the US Department of Agriculture, phosphates are safe when added within the permitted concentration of 0.5%, but such additives generate adverse reactions from the consumer.

Our research has examined high pressure to compensate for reduction in salt and/or phosphate in frankfurters and sausages. High pressure is obtained using a hydraulic pump and is applied to the products via a pressure-transferring medium. This results in uniform pressure transmission throughout the product, independent of product shape and size. Being a non-thermal process, product flavour and nutritional qualities are maintained.

Our results indicated that frankfurters treated with high pressure (150MPa) had lower cooking losses than non-pressure treated products. Emulsion stability and texture of pressurised products were as acceptable as control frankfurters. Cook yield was also enhanced when phosphate concentration was reduced to 0.1%, and texture was improved in reduced-salt frankfurters after 300MPa pressure. Pressure treated (150MPa) sausages had similar stability and overall acceptability as non-treated products and texture profile analysis was enhanced when the phosphate was reduced to 0.25% after the pressure treatment. Overall flavour intensity of breakfast sausages with 0.25% phosphate was not affected by the pressure treatment.

Although high pressure treatment is a batch process, these results are positive for the processed meat industry as a novel route to the production of additive-reduced meat products. Further investigations into minimal processing in the Meat Technology Department are concentrating on the use of high intensity ultrasound as a rapid, energy efficient technique to cook pressurised meat products.

FE475 Analysis of Tomato Paste

FE475 FOOD QUALITY CONTROL LABORATORY

ANALYSIS OF TOMATO PASTE

GROUP = B – 2 HAKAN MAVİŞ

FE475 Food Quality Control Laboratory

ANALYSIS OF TOMATO PASTE

Purpose:

The purpose of this experiment was to analyze different tomato paste labels and to compare properties of these tomato pastes with each other, and to inquire about tomato paste standards and adulteration

Theory:

Industrial tomato products users should rigorously evaluate tomato products suppliers based on long-term, fundamental characteristics important to users intent on achieving advantageous values.

When tomato products prices are high, there is always expansion; when there is oversupply creating lower prices, there is always contraction. Do all new entrants to the industrial tomato products industry offer product quality and cost advantages to users through improved design, technology and organization? Which suppliers may quit the business and terminate production of tomato products? What are your concerns in evaluating industrial tomato products supply?

It takes only one page to outline intent, and even less to say, “We are the foremost industrial tomato products supplier in our industry.” However, it takes considerably more to discuss the criteria that will enable the discriminating tomato products user to rigorously evaluate our commitment to achieve a high level of performance. The following discussion applies to the production of tomato paste; however, most factors also apply to diced tomatoes.

(A) Tomato Product Quality that not only meets the user’s specifications, but is consistent from container to container.

(1) Higher quality fresh tomatoes;
(2) Faster and gentler handling of fresh tomatoes from field to hot-break tank;
(3) Good hot-break temperatures followed by lower evaporation and sterilization process temperatures;
(4) Faster movement of product through the process, decreasing the time product is exposed to elevated temperatures, and;
(5) Maximum blending of fresh tomato loads and product through a dedicated process line to equalize the naturally varying quality of incoming fresh tomatoes.

(B) Tomato Product Price that provides a competitive edge in favor of the user.

(C) A Tomato Product Supplier intently responsive to the user’s need for:

(1) prompt, accurate invoicing and shipping service;
(2) sound technical support service for product issues;
(3) quick, authoritative decisions on issues impacting the business relationship;
(4) knowledge of technologies and industry forces impacting their business and the structure of the tomato industry, and;
(5) personnel and ownership intent on maintaining themselves at the forefront of tomato processing–as innovators and true professionals.

(A) Tomato Paste Quality.

The best quality is that which consistently meets the customer’s specifications. However, most customers’ specifications have acceptable parameters rather than absolute targets. For example, viscosity may be specified as 5 to 7 cm. Bostwick, instead of 6 cm. This is due primarily to historical technological limitations, as well as the relative acceptance of product variability by the consumer. However, if such technology and ability were available to the producer, a specific or narrower range of targets would be advantageous in most users’ manufacturing environments. Furthermore, with a narrow range of targets, manufacturing would benefit from using tomato paste that is consistent from container to container during the daily manufacturing process, be it a 5.2 cm. or a 6.5 cm. Bostwick specification.

Aside from individual user’s unique specifications for particular finished products, “high quality” tomato paste is considered to have high color, nutrient retention and serum viscosity (assuming “hot-break” paste), plus low mold and defect levels.

How is the level and consistency of quality achieved by the tomato paste producer?

The tomato paste manufacturing process utilized by Morning Star is shown in Exhibit 1. All manufacturers of tomato paste have similar processes; however, each is unique in the type of equipment utilized and manner in which the equipment is combined to form a “process.” A more consistent and higher level of tomato paste quality will be produced with:

1) Most critical tomato paste quality attributes are inherent in the fresh tomato. The tomato paste manufacturing process can only be designed and operated with the objective of not deteriorating the natural quality of the fresh tomato–the process can not improve quality attributes not present in the fresh tomato. Therefore, it is critical that “high quality” be present in the fresh tomato in order to obtain “high quality” in the tomato paste.

Given the importance of quality in fresh tomatoes, Morning Star purchases tomato varieties based on their potential for (a) satisfying customers’ specifications, and (b) costly effective manufacturing. These are the sole incentives Morning Star has in directing its tomato variety program. The personnel and ownership of Morning Star have their primary interests and assets focused on processing.

2) Assuming a given level of quality in the fresh tomatoes, shorter time and gentler methods of handling, from the growers’ fields to initial processing, will result in a minimum of deterioration of the fresh tomato’s quality. The standard method in the industry is to detour loads of tomatoes to a grading station somewhere between the fields and the facilities, increasing distance and delays. At Morning Star, as well as about 50% of the facilities, tomatoes are hauled directly from the fields to our facility where the weighing and grading of tomatoes takes place by State supervised inspectors, saving precious time.

When tomato loads are weighed and graded, the information is entered into our computer, and a special program operates to blend loads by assigning an unloading order for each load based on its potential viscosity and mold level. Tomatoes are unloaded in a covered shed, elevated over twenty feet above grade, and transferred by gravity between wash systems, eliminating severe handling, which is inherent in processes using elevators.

3) The specific impact the tomato paste manufacturing process has on the color and viscosity of tomato paste is in the quantity of heat units applied to the product. This is a combined function of time and temperature. Shorter holding times and lower evaporation and sterilization process temperatures (beyond the initial high temperature “hot-break” stage), result in higher quality tomato paste.

The process times and temperatures in each facility should be compared. Most new facilities have installed four-effect (utilizing steam energy input four times), four or five stage evaporators. We have installed triple-effect evaporators to accomplish ninety percent (90%) of the evaporation task and double-effect finishing evaporators for the balance. The advantages of lower temperatures, less maintenance, and higher operating efficiency with triple and double effect evaporators considerably outweigh any steam energy savings. Morning Star has steam injection sterilizing and standard flash cooling. This sterilization process is very efficient in achieving a rapid increase to sterilization temperature and an immediate decrease in temperature upon achieving sterilization in the flash cooler. Low fill temperatures arrest chemical degradation of the product once packaged.

4) Fast movement of product through the process to minimize the residence time of product at elevated temperatures is achieved by: (a) high and continuous product flow rates, plus (b) a minimum of product “tankage.” One should review facilities for simplicity of design and process, characterized by low energy and low labor input per unit of production as an indication of the amount of work required by the process. This translates into high and continuous flow rates due to fewer breakdowns and complications.

The best measure of residence time is the throughput rate relative to the total tankage in the facility. With a relatively small increase in tankage, Morning Star’s throughput rate is the highest of all facilities producing for the industrial tomato paste market.

5) A thorough blending of tomato loads from the fields and through the process is absolutely critical in the production of tomato paste that is consistent from container to container! Consistent quality ingredients are required for a using manufacturer to produce consistent quality finished products with minimal formulation changes, resulting in lower costs.

The viscosity (as well as other quality attributes), inherent in each load of fresh tomatoes, varies widely. This is due not only to the many different varieties grown, but to the irregularities within a variety resulting from variable growing conditions. From 20 to 40 different varieties are purchased by a given processor, in a given year, from over 160 commercially grown varieties in California today. Normal variation in the viscosity potential of fresh tomatoes from load to load is one to two centimeters Bostwick.

Results and Calculations:

Group

Black Point

Reducing sugar % g.

Brix

Acidity % g. in dry matter

Salt content % g. in dry matter

1. TAT

2

14,110

21

12,840

14,60

2. DEMKO

1

12,535

27

10,450

2,16

3.PENGUEN

4

8,400

27

9,137

2,77

4. ÖNCÜ

13,700

27

9,420

2,38

5. HOME MADE

1

11,110

20

8,220

41,00

6. HOME MADE

8,879

21

8,047

39,52

7. HOME MADE

3

12,707

30

6,940

28,30

8. HOME MADE

3,571

7

4,388

66,74

9. HOME MADE

3,570

12

3,730

41,20

10. HOME MADE

10,365

31,5

4,940

24,38

11. HOME MADE

6

3,875

35

1,664

9,93

TSE

Black point

Max. 2 in 1 g

Reducing sugar

Min. 40 % (w/w)

Brix

Min. 11 % puree

Min. 28 % double conc.

Min. 36 % triple conc.

Acidity %g. in dry matter

Max. 10 % of total solid

Salt content % g. in dry matter

10 % of total solid

  • Brix: was measured by refractometer.

Brix= 4, 5 * 6 = 27, 0                        (1:6 dilution factor)

  • Acidity: 10 g tomato paste + 50 g water = 60 g tomato paste solution

6, 7 ml 0,1N NaOH was spent

(10 g tomato paste * 10 ml solution) / 60 g solution = 1, 52 g tomato paste in 10 ml solution.

If 1 ml of 0, 1 N NaOH = 0, 0064 g citric acid

(0, 0064 g citric acid * 6,7 ml NaOH) / 1 ml NaOH =0,043 g citric acid

(0, 043g citric acid * 100 g tomato paste) / 1, 52 g tomato paste = 2, 83 g citric acid

(100 g in soluble solid * 2, 83 g citric acid) / 27 g soluble solid = 10, 45 % in dry matter

  • Salt content: 10 g tomato paste + 90 g ml water = 100 g tomato paste solution and 100 g tomato paste solution was completed to 500 ml.

2 ml 0,05N AgNO3 was spent

From 500 ml, 50 ml solution was taken and this solution contained 1 g tomato paste.

If 1 ml of 0,05N AgNO3 = 0, 00292 g NaCl

(0, 00292 g NaCl * 2 ml AgNO3) / 1 ml AgNO3 = 0, 00584 g NaCl

(0, 00584 g NaCl * 100 g tomato paste) / 1 g tomato paste = 0,584 % NaCl in dry matter.

(100g tomato paste * 0, 584 g NaCl) / 27 g = 2,16 g NaCl

  • Reducing Sugar: 20,3 ml of solution was spent

mg reducing sugar im 100 ml = (total reducing sugar required / liter ml) * 10

                                                = (50, 9 / 20,3) * 100

                                                = 250, 7 mg reducing sugar

(250, 7 mg reducing sugar * 100g tomato paste) / 2 g tomato paste =12,535 g reducing sugar

Note: 50, 9 was found from Lane – Eynon method page 30. 20, 3 ml titer was equal to 50, 9

  • Black point: 1 was observed black point between two glaas.

Discussion:

Tomato processing is seasonal, with a limited period of only 60–100 days per year. There are a very large number of different varieties of tomatoes, and the quality also depends heavily on climatic conditions and weather. For all manufacturers, the main requirement is therefore to have an efficient, reliable and versatile processing plant that is in continuous operation. Manufacturers are constantly on the lookout for any possible means to improve both quality and yield. Separation plays a major role in their ability to do this.

A wide range of products can be obtained from tomatoes, including tomato juice, paste, diced-peeled tomatoes, strained tomato pulp, sauces and powder. For the industrial market, tomato paste is probably the most important product because it is used as the basis for a wide range of other products. In general, the fruit is washed, sorted and pre-conditioned by crushing, peeling or cutting it to the required size. Depending on the particular requirements, the pre-conditioned fruit then undergoes heating, refining, pulping, reconditioning, evaporation, pasteurization and packing. Separation is a key part of the reconditioning stage of this process. By removing any moulds present, separating out the pulp and clarifying the juice, the manufacturer can control the colour, mould content and viscosity of the final product. These are the key parameters that determine quality, and thus have an influence on value further down the value chain.

In this experiment; we analyzed different labels tomato paste. These were demko, tat, öncü, penguen, home made tomato pastes.

Firstly; we measured the brix of tomato paste. Brix was measured with refractometer. Brix is important parameter for tomato paste. It shows amount of soluble solid in tomato paste. This value according to TSE, min 11 % and in double concentrated 28 %. In triple concentrated 36 %.we measured brix as 27 % and this value was appropriate TSE.

Secondly; we observed black point. Black point results from poor sorting, trimming and it is undesirable. In here; seed and skin of tomato are peeled off completely. Skin or seed exposes to heating process and burns. It appears as black point. We observed one black point in gram.

Next; we measured the salt content in tomato paste. At our analysis, we calculated 2, 16 % in dry matter. According to TSE this value is max 10 %. Our value is less than TSE value. May be during titration silver nitrate may have been added few drops. But 2, 16 can be appropriate to TSE value and analysis was true. In addition; salt gives viscosity and can increase the brix, thus salt can be used for adulteration.

Viscosity is important parameter for tomato paste, as it has a direct effect on the final product. The tomato juice from the refiner normally contains 38–45 % pulp. The aim is to produce a paste with the greatest possible level of pulp that can still be pumped effectively to the evaporator, because this reduces evaporation costs. The clear juice from the decanter centrifuge can be used to adjust the colour and viscosity of the paste until it has the required characteristics. However, it can also be used in other related production processes, such as diced and peeled tomatoes. This makes sure that nothing goes to waste, and also enables companies to diversify their product line. Each individual batch of tomatoes has its own unique characteristics.

Then; we measured the acidity of tomato paste. Acidity affects the taste of tomato paste. It was calculated 10, 45 % in dry matter. According to TSE, our result was appropriate.

Finally; we measured reducing sugar. Our result was calculated as 12, 535 % but TSE value is 40 %. That is; our result is not appropriate to TSE value. During titration making, anything was made wrong, this wrong affected our result.

Laboratory‎ > ‎Analysis of Oils and Fats ( Hakan MAVİŞ )

FE475 FOOD QUALITY CONTROL LABORATORY

ANALYSIS OF OILS AND FATS

GROUP = B – 2

M. HAKAN MAVİŞ

Purpose:

The purpose of this experiment was to analyze different oils and fats labels and to compare properties of these oils and fats with each other, and to inquire about oils and fats standards.

Theory:

Olive oil: production, trade quality, and composition

The olive tree belongs to the botanical family of Oleaceae, the most important species being Olea europea sativa. It is characterized by its extended life span. The olive tree has adapted to heat and dryness and is therefore well suited to the environment in which it grows. The ideal conditions for its growth are at a mean temperature of 15 to 20 °C, i.e. especially in Mediterranean countries. During maturation, the oil content of the olive increases and reaches 15 to 30% weight of the total fruit. Harvesting takes place from November to February, using the traditional method of hand picking. Beating the olives off the tree with poles considerably increases the quantity of olives collected per day. The olives are collected in large light synthetic fibre nets positioned under the trees. After harvesting, the fruit has to be sorted, especially when it has been collected from the ground.

o   Native olive oils

Native olive oil is oil obtained from the olive by mechanical or other physical means. It is the oily juice of the fruit and not (in contrast to other vegetable oils) a seed oil. Native olive oil is virtually the only oil that can be consumed as it is actually obtained from the fruit, and when properly processed, maintains the taste and odour of the fruit unchanged.

Firstly, the olives are washed to eliminate any remaining impurities (e.g. dust or soil). Then they are crushed whole, without prior stoning, in roller mills or by modern hammer crushers. For separating the solids and liquids, the olive paste is spread onto a pulp mat, which is then stacked onto other mats to form a cylindrical load held fast by a central guide. The pressure exerted on the stack causes the liquids to run while the solids (pomace) are retained on the pulp mats. The vegetable water and oil gradually seep out, running down into a set of decanters. The mixture of water and oil produced by this traditional pressing method can be separated by gravity in decanting vats. A more rapid separation can be achieved in centrifuges.

By using modern technology the process is simplified. The pomace, oil and vegetable water are separated by continuously centrifugating the paste. After being suitably thinned with lukewarm water, the paste is injected into centrifuges. Because of the different densities of the three substances, an immediate separation can be achieved.

o   Refined olive oil

Native olive oils that have defects in the form of a low sensory rating (see appendix) and/or a high free acidity have to be made fit for consumption by refining. The process of refining includes neutralisation, decolouration and deodorising. Neutralisation is for eliminating the excess of free fatty acids in the oil. Alkaline bleaches (e.g. sodium hydroxide) are normally used for this process. Minor quality oils often have an intense or abnormal colour which has to be corrected by decolouration. This is a physical process carried out by “surface absorption” with natural colourings being absorbed onto substances such as bleaching clay and active carbon. The purpose of deodorising (treating the oil with steam in a vacuum at high temperature) is to eliminate defective odours and flavours in the oil.

Olive oils that have been refined are pale in colour and not very viscous. They have little or no taste or odour and a very low acidity.

o   Trade quality

Olive oil is traded on the international market at a higher price than other vegetable oils. Consequently, adulteration of olive oil with cheaper oils is a temptation. To guarantee a fair trade and to protect consumers, the European Commission (EC) (1) has introduced definitions and fixed criteria for olive oil and olive-pomace oil. These criteria are set in place to distinguish the different types of olive oils and to protect their quality and purity. They include limits for the fatty acid composition, free fatty acids, aliphatic alcohols, the content and composition of sterols, erythrodiol and uvaol, the peroxide level and the presence of saturated fatty acids at the 2-position within the triglycerides and trilinolein. The criteria also define the sensory characteristics for virgin olive oils.

Used generically, the term olive oil means the oil obtained solely from the fruit of the olive tree. It also excludes mixtures with oils of other kinds. Olive-pomace oil may not use this term either. Olive oil may be called by one of the following designations provided it complies with the relevant criteria fixed in the standard.

Virgin (or native) olive oils are oils obtained from the fruit of the olive tree by mechanical or other physical means under conditions, particularly thermal conditions, that do not lead to the deterioration of the oil. Virgin oils have not undergone any treatment other than washing, crushing, pressing, centrifugation, and filtration. When virgin olive oil is intended for consumption in its natural state, it is called by one of the following names:

  • Extra virgin olive oil – a virgin olive oil that has a sensory rating of 6.5 or more (see appendix) and a content of free fatty acids, expressed as oleic acid, of not more than 1 gram per 100 grams.

  • Virgin olive oil – a virgin olive oil with content of free fatty acids of not more than 2 g per 100 g. (Sensory rating of at least 5.5.)

  • Ordinary virgin olive oil is a virgin olive oil that has a content of free fatty acids of not more than 3.3 g per 100 grams. (Sensory rating not more than 3.5.)

Olive oil is the oil consisting of a blend of refined olive oil and virgin olive oil that is deemed independently fit for consumption.

Olive-pomace oil is the oil obtained by treating olive pomace with solvents. It can be classified as follows:

  • Refined olive-pomace oil is obtained from crude olive-pomace oil by refining.

  • Olive-pomace oil is a blend of refined olive-pomace oil and virgin olive oil that is deemed independently fit for consumption. In no case whatsoever may it be called “olive oil”.

The different grades of olive oil and olive-pomace oil are identified by the purity and quality criteria laid down in the trade standards of the EC. For each grade, minimum or maximum limits for the content of the different parameters are prescribed.

  • Composition of olive oil

Olive oil is a mixture of glycerides, which are esters of glycerol with fatty acids. In addition, olive oil contains small amounts of free fatty acids, glycerol, phosphatides, flavour compounds, sterols and other minor components.

The major fatty acid of olive oil is the monounsaturated oleic acid (C18:1). The mean fatty acid composition of olive oil is as follows:

Palmitic acid (C16:0) 7.5-20%

Palmitoleic acid (C16:1) 0.3-3.5%

Stearic acid (C18:0) 0.5-5.0%

Oleic acid (C18:1) 55.0-83.0%

Linoleic acid (C18:2) 3.5-21.0%

Others 1.5-3.2%

The fatty acid composition of olive oil is influenced by different factors, such as the variety of the olive tree, agricultural and climate factors.

The nonglyceride fraction of olive oil comprises several groups of compounds: nonglyceride fatty acid esters; hydrocarbons; sterols; triterpene alcohols; tocopherols; phenols; phospholipids; chlorophylls; and flavour compounds (see below).

Although the largest proportion of fatty acids is esterified with glycerol, small quantities of fatty acids form esters with a variety of other alcoholic compounds, including methanol, ethanol and triterpene alcohols. The main triterpene of olive oil is squalene, a biochemical precursor of sterols. Olive oil is richer in squalene than most vegetable oils. Furthermore, there are different polycyclic aromatic hydrocarbons present in olive oil, as well as small quantities of b -carotene. The main sterol present in olive oil is b -sitosterol which accounts for about 95% of the total sterols. Campesterol represents 3%, the remaining 2% are a mixture of other sterolic constituents.

Most of the tocopherol in olive oil is a -tocopherol which has the highest vitamin E activity. Its content is on average 15-25 mg/100g. In general, native olive oils have a higher vitamin E content than refined olive oils.

The olive mesocarp contains phenolic compounds which are mainly water soluble. Some quantities of phenolics, however, are carried into the olive oil. The main polyphenols of olive oil are tyrosol and hydroxytyrosol, derived from the hydrolysis of oleuropein, the bitter component of the olives. Benzoic acid and cinnamic acid, probably originating from the degradation of flavonoids, are also present in olive oil. The phenolics of olive oil decrease its oxidation rate, because they are potent antioxidants. Virgin olive oil has a characteristically pleasant flavour. The main groups of flavour substances are aliphatic and aromatic hydrocarbons, aliphatic and terpenic alcohols, aldehydes, ketones, ethers, esters, furan and thiophene derivatives. The flavour complex changes as the oil deteriorates with storage time.

Analytical quality controls for olive oil

Acidity

Lipolytic processes in the olive start to break down the triglycerides in the maturation stage. This becomes more prevalent at harvesting. These lipolytic processes are intensified by hydrolysis and autoxidation, leading to the formation of free fatty acids which decrease the sensorial quality of the oil. The lower the content of free fatty acids the higher the quality of the oil.

The content of free fatty acids is mainly influenced by the time of harvesting, the duration between harvesting and processing, and storage conditions of the olives.

Peroxidation

Lipid peroxidation leading to oxidative rancidity is the main change causing deterioration of olive oil during storage. It is due to oxidation of unsaturated fatty acids initiated by free radicals and the subsequent formation of compounds possessing unpleasant taste and odour.

The formation of peroxides depends on several factors. All influences which promote the formation of free radicals such as light, high temperature and contact with metals increase lipid peroxidation. Thus, conditions and duration of storage of both the olives and the oil are of great importance.

Purity parameters

The sterol, erythrodiol, uvaol and alkanol contents are very important for the investigation of the quality and purity of olive oil. These minor components cannot be converted or broken down but can be separated from it by suitable techniques.

The composition of sterols

It is unique for each vegetable oil. For olive oil, b -sitosterol is the main sterol, and also campesterol is present in measurable amounts. If other sterols can be detected, it is an indicator for an adulteration with other oils or fat, for example, substitution of sunflower oil for part of the olive oil is reflected by the presence of stigmasterol, which is absent from olive oil.

The total sterol content

It is much higher in native olive oils than in refined oils. Thus, the amount of sterols can indicate if a native olive oil has been adulterated with a refined olive oil. A minimum content for native olive oils is prescribed according to the EC-regulation.

The content of erythrodiol and uvaol is much higher in olive-pomace oils than in olive oils, so their presence shows if part of the olive oil has been substituted with olive-pomace oil.

Another parameter of purity is the stereospecific distribution of major fatty acids between the 1,3 and 2-position of glycerol in the oil. All vegetable oils are characterised not only by a specific fatty acid composition, but also by a specific distribution of their fatty acids within the triglycerides: saturated fatty acids are concentrated at the 1,3-positions and almost absent at the 2-position which is generally occupied by unsaturated fatty acids. If the proportion of saturated fatty acids at the 2-position is increased in olive oil then it can be assumed that there is an adulteration with a synthetic ester oil.

Sensory quality criteria of olive oil

The sensory analysis of virgin olive oil is based on a panel test, developed by the International Olive Oil Council. In this test, 8-12 selected, trained tasters analyse the flavour (which includes taste and odour) of virgin olive oil as well as the intensity of the different flavour attributes. (Examples for positive attributes are: “apple”, “fruity”, “green leaves”, “grass”, “bitter”, “harsh”, “sweet”; and for negative attributes: “winey-vinegary”, “metallic”, “earthy”, “muddy sediment”, “fusty”, “rancid”.)

The final rating is awarded on the basis of a scale of points running from 0, which indicates that the oil has extreme defects, to 9, which indicates that it has no defects at all. For extra virgin olive oils, the rating must be at least 6.5.

There are more than 50 varieties of olive trees leading to the specific odours, tastes and colours of the olive oils. For example, the olive oil from Tuscany may be fruity, but a little bit pungent, while oils from Malaga are often characterised by a light taste and a golden colour.

Furthermore, the sensory properties of oil are influenced by agricultural and climatic factors as well as by time and method of harvesting.

Results and Calculations:

sample

Saponification

FFA %

Iodine number

Peroxide value

Colour

R I

1- kristal olive oil

Blank 0,2

0,225

12,26

0,8

Yel 1,1

red 0,1

1,468

2- komili olive oil

116,4

0,39

Blank 0,1

9,4

Yel 2

red 0,3

1,468

3- ona sunflower

22,44

0,282

18,52

Blank 0,3

Yel 0,6

red 0,1

1,472

4- yonca sunflower

25,2

0,0564

21,3

3,4

Yel 0,7

red 0,1

1,472

5- luna maize oil

151,2

0,9024

18,78

1,4

Yel 0,7

red 0,1

1,469

6- bizim maize oil

123,42

0,4512

15,28

2,8

Yel 1,4

red 0,1

1,472

7- teremyağ marga

186,53

0,451

 

3,0

Yel 6,3

red 1,2

1,469

8- sana margarine

57,5

0,3948

24,36

0,6

Yel 5,5

red 1,1

1,325

9- komili olive oil

109,3

1,003

17

2,0

Yel 2

red 0,3

1,468

10- used olive oil

179,5

2,37

9,73

2,4

Yel 1

red 10

1,469

11- Ülker bizden…

131,8

0,6768

29,69

0,8

Yel 5,5

red 1,1

1,480

Ø  Saponification value = [(B – A) / wt of sample] * 28,05

Saponification value = [(8,5 – 0,2) / 2g] * 28,05 = 116,40

Ø  % Free Fatty Acid = (V * 28,2 * N) / wt of sample g

% Free Fatty Acid = (0,7 * 28,2 * 0,1N) / 5g = 0,39 %

Ø  For iodine value  we prepared the blank = 0,1 ml 0,1N Na2S2O3

Ø  Peroxide value = [(S – B) * N * 100] / wt of sample g

Peroxide value = [(5 – 0,3) * 0,1N * 100] / 5g = 9,4 %

Ø  Colour redness = 0,3 and yellowness = 2,0 with Lovibond Tintometer.

Ø  Refractive index = 1,468 with refractometer.

Discussion:

In this experiment we studied oils and fats analysis and depending on these analyses the composition of oils and fats were examined we analyzed some different labels of oils and fats according to saponification value, free fatty acid content, iodine value, peroxide value, colour and refractive index.

These tests display us some different characteristics of oils and fats that is used for quality degree.

Saponification value is an important parameter for oil and fats. Saponification value shows the weight of potassium hydroxide in mg required saponifying 1g of the oils and fats.

Free fatty acid content is crucial parameter for oils and fats. Free fatty acid content is usually calculated as oleic acid. If free fatty acid content is high oil and fat is to spoilage and free fatty acid is high and FFA content is harmful for human health. In addition; free fatty acid content shows an index of degree of hydroylsis of triglycerides (hydrolytic rancidity).

Iodine value is important for oil and fats because iodine value display the unsaturated bonds. Unsaturated bonds show the saturated ratio of oil and fat. Unsaturated bond containing oils is usually preferred.

Another important parameter is a peroxide value. Peroxide value shows that during storage of oils and fats, oxygen is absorbed of the unsaturated bond which reacts like those in peroxide. At peroxide value we examined the spoilage ratio arising from peroxide. That is; amount of oxidative deterioration (oxidative rancidity).

Another important parameter is a refractive index. Refractive index shows oil and fat whether unsaturated or saturated. If refractive index is high melting point is low and we understand that oils and fats are unsaturated.

Finally; we examined the colour of oil with Lovibond Tintometer and we measured approximately yellowness 2 and redness 0, 3.

After experiment saponification value was measured as 116, 4 ml this value is appropriate to TSE value, then free fatty acid content was measured as 0, 39 %. TSE value is maximum 0, 3 therefore our result was appropriate to TSE value. Next; iodine value was examined but we prepared the blank solution value of blank solution was measured as 0, 1. After that; peroxide value was measured as 9, 4 and TSE value is max. 20 therefore; our value is proper to TSE value. Then refractive index was examined and by refractometer was measured as 1, 468. this value also is suitable to TSE value. Finally; we said that examining oil had been produced according to TSE value and was standard oil.