Food Science Terms - P

Palatability: Pleasant to taste, being acceptable. 

Panning: process of building thin layers of sugar, sweetener or other coating onto food (eg nuts, fruits)

Pantothenic acid: One of the B vitamins. 

Papain: enzyme found in papaya used as tenderizing agents

Parasite: Animal or plant that lives in or on another from whose body it obtains nourishment. 

Pasteurization: Process, temperature and time, designed to reduce the population of pathogenic bacteria in a product, sufficient to ensure product safety but with modest impact on the nutritional properties and flavor of the product. Traditionally, this term has been applied to thermal processes but it can also refer to emergent alternative technologies with the purpose of pathogens inactivation. For milk it requires a temperature of 72°C for 15 sec.

Pasteurized: Milk or milk product that has been exposed to a process of pasteurization wherein every particle of that milk or milk product is heated in properly designed and operated equipment to a specified temperature and then held continuously at or above that temperature for at least the corresponding specified time. Pasteurization eliminates pathogen (disease causing bacteria) contamination in milk and products derived from milk. 

Pasteurized process cheese food: Variation of process cheese that may have dry milk, whey solids, or anhydrous milkfat added, which reduces the amount of cheese in the finished product. It must contain at least 51% of the cheese ingredient by weight, have a moisture content less than 44%, and have at least 23% milkfat. 

Pasteurized process cheese spread: Variation on cheese food that may contain a sweetener and a stabilizing agent, such as the polysaccharide xanthan gum or the Irish moss colloid carrageenan, to prevent separation of the ingredients. The cheese must be spreadable at 70degF, contain 44 to 60% moisture, and have at least 20% milkfat. 

Pasteurized process cheese product: Process cheese that doesn't meet the moisture and/or milkfat standards. 

Pathogen: usually a living microorganism (bacteria or virus) that can cause disease

Pathogenic: Capable of causing disease; harmful; any disease-causing agent. 

Peak voltage: Maximum voltage (kV) delivered by PEF system. 

Pectin: structural component found in plant cell walls which can be used for thickening and gelling . It is a natural gelling agent and principally used in making jams and jellies. Some fruits are high in pectin content (e.g. apples). Others such as strawberries and raspberries have very little pectin and for these additional pectin (e.g. from Sure-Set sugar) can be very helpful. 

Penetration depth: Distance the electromagnetic waves (of a certain frequency) travel in a material before it loses 63% of its energy. 

Penetrometer: Measurement of the gel strength (the penetration of a plunger of a defined size and weight into the gel is measured). 

Perishable: Having a short shelf-life; food that spoils quickly and needs careful storage. 

Peroxide Value (PV): Measures the amount of peroxides and hydroperoxides in a sample of fat produced in the oxidation process. 

Personal hygiene: Way a person maintains their health, appearance and cleanliness. 

Pesticides: Chemicals used to kill pests. 

PET: Polyethylene terephthalate, a light-weight clear plastic with acceptable barrier properties to gas and water vapor. 

PGA: Polygalacturonic acid. 

pH: Scale used to express acidity or alkalinity, from 1 (strong acid) through 7 (neutral) to 14 (strong alkali). The scale is logarithmic, so pH 4 is ten times as acidic as pH 5 and pH 2 is ten times as acidic as pH 3, and so on. pH is a measure of the activity of the hydronium ion (H3O+) which, according to the Debye-Huckel expression, is a function of the concentration of the hydronium ion [H3O+], the effective diameter of the hydrated ion and the ionic strength (µ m) of the solvent. For solutions of low ionic strength (µ m < 0.1) hydronium ion activity is nearly equivalent to [H3O+] which is normally abbreviated to [H+]. Then, for a weak acid (HA) dissociating to H+ and A- with a dissociation constant, Ka and pKa equal to -log10 Ka, the most important relationships are defined the following two equations: Ka = [H+] [A-] / [HA] and pH = log 1 / [H+] = pKa + log [A-] / [HA] 

pH value: Measure of the acid/base properties of a substance. 

Phytate: Chemical complex (large molecule) substance that is the dominant (i.e., 60 to 80%) chemical form of phosphorous within cereal grains, oilseeds, and their by products. Monogastric animals (e.g., swine) cannot digest and utilize phosphorus within phytate, because they lack the enzyme known as phytase in their digestive system, so that phosphorus (phytate) is excreted into the environment. 

Physical hazard: Particles or fragments of items not supposed to be in foods. 

Phytochemical: Substances found in edible fruits and vegetables that may be ingested by humans daily in gram quantities and that exhibit a potential for modulating the human metabolism in a manner favorable for reducing risk of cancer. 

Pickle pond: Pond where high-density brine is stored. 

Pickling: Practice of adding enough vinegar or lemon juice to a low-acid food to lower its pH to 4.6 or lower. Properly pickled foods may be safely heat processed in boiling water. 

Plasticizing (votation): Purpose is to develop the finest possible crystal structure in order to produce a shortening or margarine that is smooth in appearance and firm in consistency. 

Plato, degrees: Expresses the specific gravity as the weight of extract in a 100 gram solution at 17.5°C. Refinement of the Balling scale. 

Polymerization: Undesirable change in the composition of a food fat involving intermolecular agglomeration or clumping of the normal chemical units of fat and its decomposition products into larger and insoluble chemical units. 

Polyols: Type of sweetener used in reduced-calorie foods. They differ from intense sweeteners in that they are considered nutritive; that is, they do contribute calories to the diet. Polyols are incompletely absorbed and metabolized, however, and consequently contribute fewer calories than sucrose. The polyols commonly used in the United States include sorbitol, mannitol, xylitol, maltitol, maltitol syrup, lactitol, erythritol, isomalt and hydrogenated starch hydrolysates. Most are approximately half as sweet as sucrose; maltitol and xylitol are about as sweet as sucrose. Polyols are found naturally in berries, apples, plums and other foods. They also are produced commercially from carbohydrates such as sucrose, glucose, and starch for use in sugar-free candies, cookies and chewing gum. Along with adding a sweet taste, polyols perform a variety of functions such as adding bulk and texture, providing a cooling effect or taste, preventing the browning that occurs during heating and retaining the moisture in foods. 

Polysaccharides: Carbohydrates made up of 8 or more monosaccharide units.

Post harvest waxes: After a fruit or vegetable is picked, it continues to need moisture to stay fresh and edible. To help retain moisture, certain varieties of fresh produce are given new wax coating to replace the natural wax the fruit or vegetable loses during harvest and shipping. If a fungicide is mixed with the wax to prevent molding, retail stores must label the waxed produce.

Polysaccharide: complex carbohydrate formed by long chains of monosaccharide units, joined together by glycosidic bonds

Potable water: Water from an approved source which meets all drinking water quality standards. 

Potentially hazardous foods: Food that is natural or man-made and is in a form capable of supporting the rapid and progressive growth of infectious and toxin-producing microorganisms. The foods usually have high protein and moisture content and low acidity. 

Power cycling: Process of the microwave source turning on and off. 

ppm (parts per million): Concentration of one ingredient in another; e.g. 1g per 1 Liter is 1ppm 

Prague: Powder Curing Salts. A salt-based carrier of meat curing chemicals. When used correctly, 4oz. of formulation salt can be substituted for 4oz. of Prague Powder, providing the exact 156 ppm maximum cure to 100 lbs. of meat. 

Prandial: relating to eating a main meal

Prebiotic: indigestible plant component whose consumption promotes growth of beneficial bacteria in the large intestine

Precipitation: When a chemical reaction taking place in a liquid results in the formation of a solid product, then the solid product tends to fall (i.e., it "precipitates") out of the liquid. The process is called "precipitation" and the product is called a "precipitate." 

Preparation Area: Space provided for the total processing of foods from raw to ready-to-eat. The total preparation area often is divided into functional areas based on the type of work done in the area and the type of equipment used. Examples of preparation areas include bakery, cold food preparation, and hot food preparation. 

Pre-plate: System in which food is portioned and plated at a central production facility before it is sent to a receiving kitchen. 

Preserve: Maintain quality and safety of food by removing moisture and/or air. 

Preservation index: Number calculated to show that the amounts of acid, sugar and salt used in pickles will be enough to prevent spoilage. 

Preservation: Process used to slow or stop the progress of spoilage. It allows easier distribution and transport and the food can be stored for longer before use. Preserving food by heat treatment, sugar, salt, acid or preservatives. 

Preservative: Additive that prolongs the shelf life of a food product by inhibiting microbial growth. Two examples are benzoic and sorbic acid and their sodium and potassium salts

Protein: one of the main types of macronutrient; made up of chains of amino acids

Pressure canner: Specifically designed metal kettle with a lockable lid used for heat processing low-acid food. These canners have jar racks, one or more safety devices, systems for exhausting air, and a way to measure or control pressure. Canners with 20-21 quart capacity are common. The typical volume of canner that can be used is 16 quart capacity, which will contain 7 quart jars. Use of pressure saucepans with less than 16 quart capacities IS NOT RECOMMENDED. 

Primary production: Plants and animals produced by the agricultural and fisheries sector. 

Priming: Introduction of added fermentable materials in order to enhance carbonation and give a head to the beer. Beer would be flat without it. Most home brewers use corn sugar (about 3/4 cup per 5 gallons). 

Principal display panel: Portion of the package most likely to be seen by customers at the time of purchase. Statement of identity and net quantity are must be displayed here.

Prion: Rogue protein, that appears to cause Bovine spongiform encephalopathy (BSE). 

Private label: Brand used exclusively by a wholesaler or retailer, and usually not widely advertised. 

Proanthocyanidins: Type of tannin found in cranberries, cranberry products, cocoa and chocolate which may provide the health benefits of improving urinary tract health and of reducing the risk of cardiovascular disease. 

Process (systems) audit: Can be conducted for any activity that affects the final quality of goods or services. The audit is usually made of a specific activity against a specific document, such as process operating instructions, employee training manuals, certification of personnel for critical operations, and quality provisions in purchasing documents. 

Process Authority: Based on regulations, a person or institution with expert knowledge and experience to make determinations about the safety of a food process and formulation. A Process Authority is required to maintain product confidentiality. 

Process deviation: Any critical process factor which differs outside an specified value and limit or range limit during the treatment and subsequent handling of a treated food. 

Process pressure (PP): Constant holding pressure for any HPP treatment (MPa) (psi). Process pressure should be controlled to +/- 0.5% and recorded to the same level of accuracy. (+/- 500 psi at 100,000 psi) or (+/- 3.4 MPa at 680 MPa). 

Process pressure hold time: Recorded time from end of compression to beginning of decompression(s). 

Process: Set of interrelated resources and activities that transform inputs into outputs. Resources may include personnel, finance, facilities, equipment, techniques, and methods. 

Processing: Treating a food in such a way as to change its nature and properties in order to preserve it, to improve its eating quality or to make useful ingredients. 

Product Audit: Detailed study of the products in a product mix to analyze their performance in quantitative and qualitative terms. 

Product composition: Specified percent by weight and range limit of stated product ingredients (%). 

Product initial temperature (IT): Product IT can be specified as a critical process factor. For HPP processes, IT must be not less than 0.50°C below value-value in all food locations from start of compression time to end of decompression time (°C). 

Product pH: Value of pH measured at product IT at atmospheric pressure. 

Product process temperature: Temperature at which the process is performed (°C). Initial temperature and process temperature must be monitored at all points of the process if it is an integral condition for microbial inactivation. With some processes, such as HPP, foods will increase in temperature as a function of the imposed treatment and their composition. Final product temperature at process pressure is independent of compression rate as long as heat transfer is negligible. 

Protein: Complex, nitrogen-containing substance that is found in food and is essential for the functioning of the human body. Protein molecules consist of long chains of building blocks called amino acids. Some of these amino acids can be manufactured in the human body. Others must be supplied by the diet. The body breaks down food proteins into their amino acid constituents and then reassembles the amino acids into the proteins needed for normal functioning. 

Protopectin: Bound, water-insoluble pectin, as it occurs native in fruits. 

Provitamin: Compound that the human body can convert into a vitamin. For example, beta-carotene is a provitamin because the body can convert it into vitamin A, as needed. 

Psychrophile: Microorganisms that grow best at cold temperatures, with optimum growth at 5° -20°C (41°-68°F) and are capable of growing at refrigerated and room temperatures. 

Pulp: Beet pulp is the term applied to sugar-beet slices from which the sugar has been removed by diffusion into hot water. This exhausted pulp is then usually mixed with molasses, and the resultant mixture is dried to produce "dried molassed pulp" (dmp) which is then sold as animal feed. 

Pulse rate: Number of pulses per second or input frequency (1/s). 

Pulse width: Duration of the pulse. In PEF and for exponential decaying pulse, pulse width can be calculated as the resistance of the food times the capacitor capacitance. This is also called time constant. 

Pulsed treatment: Treatment of a food using more than one treatment cycle of specified conditions such that each cycle element is accurately and precisely reproduced until a specified number is achieved. Cycle parameters (i.e. pressure, electrical field) may display a square, ramp, sinusoidal, or other waveform when recorded. 

Pyridoxine: One of the B vitamins 



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