Factors determining food quality by considering different food products

                                                                       Dairy Products

Milk:

Texture

            The texture of milk is creamy, smooth and full with moisture. The texture of milk is depend on fat globules and recovery of fat. Stability, quality and composition of milk is also affect the texture of milk.

·       Color

           The color of milk is white because it reflects visible lights of all wavelengths. Proteins such as casein, vitamins and minerals affect the color of milk. Milk color is change due to fat. More fat is present then the color will be light yellow.

·       Odor

           The smell of milk is slightly little and sweet. Due to growth of lactic acid bacteria, poor refrigeration and temperature, off-flavor will caused. When milk gets older, the bacteria that are present in milk start multiply and breakdown the lactose that cause off-flavor.

·       Taste

          Milk has bland flavor. Breed, heredity and stage of lactation affect the taste of milk. When the cow eat the feed with strong flavor, this flavor goes to udder where milk is present. Off-flavor caused by abnormal components.

·       Nutritional composition

            The fermented products that are produced from the microbes, which are present in cow, determines the composition of milk such as fat, protein and lactose. Proteins are denatured during sterilization of milk.

·       Adulteration

            Some adulterants are used in adulteration of milk such as urea, boric acid, hydrogen peroxide etc. The commercial urea is used to adulterate the milk for increasing non-protein nitrogen content.

·       Microbial Effect

            Bacterial enzymes spoil the milk. Psychrotrophic bacteria produce heat stable enzymes that are remain active in milk after pasteurization, which cause spoiling.

Butter:

      Texture

           Textural properties are depend on cow’s diet. Butter with more unsaturated fatty acids have more disperse, soft and less adhesive.

·       Color

                  The main factors that affect the color of butter are feeding method and genetic character of cow. Color also depend on fat content. Due to rancidity, its color will changed from yellow to brown.

·       Odor

                At room temperature, Fatty acids, lactones and methyl ketones that are present in better impart smell to butter. If butter is spoiled, its smell will be rancid.

·       Taste

               Rancidity cause off-flavor when lipase break into fatty acids and glycerol. Due to rancidity, its taste will be sour and bitter. When butter is rancid, it will be yellow to brown and flavor become harsh   

·       Nutritional composition

            It is rich in fat and vitamins. It has less nutritious but high caloric. Due to the presence of high amount of saturated fats, it will cause many diseases such as heart disease etc. saturated fats are strong and single bond is present in it that are not easily breakable.

·       Adulteration

             The economy get advantage by adulterate the butter that is major is major issue. They replace expensive fat with cheap fat without inform the customers.

·       Microbial Effect

              Butter has less moisture content and fatter. Molds and bacteria spoil butter. Yeast and molds cause off-flavor and discoloration in butter. Proteolytic and lipolytic changes will occur due to gram-negative bacteria.

Bakery Products

Biscuits:

      Texture

                      Texture of biscuits may be soft, flaky depend on product. Density and volume affect the texture of biscuits. Low density with increased volume softens the biscuit. It also depends on the protein content. If protein content is less then it will be soft.

·       Color

                      Dark color of biscuits is due to the presence of amino acids and high protein content in milk that do Millard reaction, which cause browning. The color of biscuits increased with baking. By increasing storage time of biscuits, the change in color is reduces.

·       Odor

                     Biscuits are chemically leavening product. It is made with baking powder and baking soda that create smell during baking and starts to brown.

·       Taste

                      Free from bitterness. Too much flour added, improper affects taste of biscuits baking and mixing.

·       Nutritional composition

                It contains vitamin A, C, K, and some minerals that are useful for children. If biscuits are made from hard flour then they contain more protein such as more gluten and if made from soft flour then contain less protein such as low gluten level. If moisture content is high then it will be soft and if moisture content is less then it will be dry and hard.     

·       Microbial effect

               Molds, yeast and bacteria affect biscuits. Molds that are grow in high water activity but it can also grow in low water activity in biscuits. The process of baking kills mold. The bacteria such as Bacillus subtilis is heat resistant bacteria that is not killed by baking.

Bread:

      Texture

              Yeast that create carbon dioxide during baking give airy texture to bread. The dough of bread will be stretchy because of protein present in flour such as gluten. The more the gluten is present, it will give firmer texture.

·       Color

                    The color of bread is occurred due to caramelization by which sweetness of bread is less because sugar is burn.

·       Odor

              The smell of bread is like yeasty and sweet. During baking, yeast produce some chemicals that break down into smelling compounds. More compound will produce; it will give more good smell.

·       Taste

              During baking, when alcohol is burn off, it leaves a flavoring component. More the fermentation of dough, more the taste will develop. Fermentation breakdown the starch that present in dough into simple sugars.

·       Nutritional composition

              Gliadin and glutenin are the proteins that are present in wheat bread. Gliadin gives it plastic nature and glutenin gives it elastic nature. They interconnected with disulphide bonds. Acrylamide that are found in bread have bad effects. Neurotoxin effect on human health.

·       Adulterants

              Bread is adulterated by potassium bromate that act as maturing agent and flour improver. During baking it, convert into potassium bromide that have effect on health and quality.

·       Microbial Effect

               Some molds such as Rhizopus destroy the quality of bread. Yeast is used in making the bread such as Saccharomyces cerevisiae that are mixed with water, flour and sugar for making bread. The bacteria such as Lactic acid bacteria improve the sensory characteristics of bread, increase shelf life and stop the growth of microorganisms.

Meat products

Chicken:

Texture

            The chemical and physical changes in muscles makes the meat tender. Rigor mortis and any softening process affects the tenderness of meat. The texture of meat is also affected by time and temperature. Tenderness is affected by connective tissues and myofibril components.

·       Color

            Some factors affect the color of poultry meat such as sex, age, fat, moisture content, processing techniques and pre-slaughtering conditions. Color of poultry meat is due to the presence of myoglobin and hemoglobin.  More color changes will occur in breast meat due to heavy weight. Environmental temperature and stress also change the color of meat.

·       Odor

            The oxidation of fat cause off odor in meat. Some factors affect the odor of meat such as feed, microbial attack and improper storage temperature.  Drip loss also spoil the smell of meat.     

·       Taste

                During cooking, the taste of meat will develop due to degradation of thiamin, interactions of sugars and amino acids and thermal and lipid oxidation. Chilling and Age of bird also effect on taste. 

·       Nutritional composition

               Meat is a rich source of protein, minerals and amino acids. The meat with high water holding capacity have high pH and less drip loss. The meat with low water holding capacity have low pH and high drip losses that cause spoil the meat. Water holding capacity is due the presence of moisture content of meat. Proteins contain nitrogenous compounds.

·       Adulteration

             Adulteration of meat with some water and liquid is restricted that inject in tissues and offal of meat. The poultry meat is injected with brine raw materials.

·       Microbial effect

                   Salmonella and campylobacter are producing due to eating poultry meat. Microbial growth occurs during processing and storage of meat. Microbial growth occurs during processing due to use contaminant equipment for standard cuts.

Beef:   

Texture

          There are some factors that affect the texture of beef such as toughness during rigor, tenderness during postmortem and denaturation of proteins during cooking. Antemortem and postmortem changes affect the texture. Softness and hardness depend on how many proteins are denatured. If more proteins are denatured then meat will be soft.      

·       Color

            The color of meat depends on the myoglobin that are present in muscles of meat. When we exposed the meat to air, myoglobin converts into oxymyoglobin that give dark red color. Color is affected by some factors such as age, sex and pH decline rate. Chemical changes occur during cooking affect the color.

·       Odor

             The odor of beef is depend on the rancidity of fat oxidation. Rancid beef has Tangy and putrid smell. When bacteria spoil the beef, it gives bad odor. The odor of beef is increased with tenderness and juiciness.

·       Taste

            Lipid oxidation cause off flavor that lowers the quality of meat. The meat flavor is affected by some postmortem factors such as pH, glycogen fatty acids, fats, proteins, temperature, marbling and some other cooking methods.

·       Nutritional composition

           It is rich in minerals, vitamins and proteins. It is depending on species and feeding. Moisture content present in high amount that are loss and dry during cooking.  Lean meat has less fat. It also contains antioxidants and bioactive compounds. It causes heart disease and cancer due to high consumption. Good for muscles due to high protein level. During cooking, proteins are denatured and burning of vitamins and minerals affect the quality of beef meat.

·       Adulteration

            Some people adulterate the beef meat by adding proteins of animal of cheaper prices and plant proteins like soybean with its components.

·       Microbial effect

            In beef meat, microorganisms spoil the products and cause spoilage. Beef with high moisture content cause microbial growth that spoil the quality of meat. Meat can also spoiled during slaughtering and by equipment that used in slaughtering.

Fruits and vegetables

Mango: 

Texture

           The mango has soft and pulpy texture. Due to ripening, the hardness of mango will increase. It can be measured by hand and penetrometer. Softness and hardness also affect taste.

·       Color

             Skin color may be green, light green and yellow in some cultivars. Red color of mango in not due to the ripeness and maturity. Flesh color will be white and orange is due to transit. The skin color of mango in not due to the ripeness and internal color. Color will be depending on cultivars. Color will show the maturity of mango. Color will also occur due to changes during ripening.

·       Odor

            During ripening of mango, the aroma compounds production will be increased.

·       Taste

         Ripening at different temperatures will tart the mango and will give undesirable taste. Softness and hardness also affect taste. More soft mangos have not good taste due to soft tissues.

·       Nutritional composition

          It contains minerals and vitamins that boost our immune system. They contain some soluble solids. When mango is hard then soluble solids will 7-9% and full ripen mango has 13-19% soluble solids. Due to ripening, starch convert into sugars that increased carotenoids and soluble solids and decrease chlorophyll.

·       Adulteration

         Calcium chloride that are carcinogenic which is prohibited but they still used for the adulteration of mangos. Due to usage of calcium chloride for artificially ripening of mangos, cause some major health issues. Calcium chloride ripens the mango and tends towards maturity.

·       Microbial effect

          In mango, stem-end root is a major post-harvest disease in which pathogenic microorganism grow. Colletotrichum spp. Microbial growth occur during transportation and storage when mango will damage and create many spots on it causes it. Microbes spoil the mango by soften it.

Potato:

·    Texture 

           Potatoes have starchy, creamy and dense texture. They may be fried and boil. Raw potatoes have starchy texture. The cooking methods affect the texture. The adhesion of cell is loss during heating. Structure and composition of cell wall determine the texture.    

·       Color

           Flavonoids and some other natural pigments give the color to potato. Anthocyanin and carotenoids impart color in the flesh of potato. When we expose the tubers of potatoes to light during storage and in home, it imparts green color.

·       Odor

            The main component of potato such as solanine present in small amount but give high level of poisoned smell that are very toxic. There are rotten potatoes, which have chemicals like smell. Potatoes contain glycoalkaloids that are harmful substance. Higher the concentration of this substance, higher will be the emission of toxic gas, which is very harmful for health when inhaled.   

·       Taste

                 The complete change in taste is occur due to cooking. After cooking, umami compounds will produce that have savory taste. After cooking of potatoes, the fatty acids degrade to produce ketones and aldehydes that give flavor. Mild sweet taste due to low sugar content.

·       Microbial effect

              Facultative anaerobes and soft root bacteria affect the potatoes. There are seven bacterial diseases that damage the potato such as pink eye, ring rot etc. Phytophthora infestans is the major pathogen of potato. Bacterial growth occur in potato because of high moisture content.

Beverages

Wine:     

Texture

            The texture of wine depend on the level of tannins, alcohol and sugars that are present in wine. High level of alcohol will have high level of glycerol. More alcohol give thickness to wine. The texture of wine is sharp, hard and smooth.

·       Color

          Color changes depend on the amount of alcohol present in wine. Low level of alcohol, enzymes, tannins and polysaccharides affect the color of wine. The color of wine is depend on main factors such as color of grape, vinification and the time of maceration.

·       Odor

         Wine have unpleasant smell due to storage. Hydrogen sulfide can give smell of wine as sewage and rotten eggs. The aroma of good wine may be fruity or citrus.

·       Taste

          Temperature is the main factor that affect the taste of wine. When tannins feel tight, they give acidic and bitter taste. The level of alcohol also determine be taste. Aging improves the taste of wine. Taste will depend on the category of grapes and amount of tannins.

·       Nutritional composition

         Nutritional composition of wine depend on the type of wine because the calories and nutrients are vary in different types of wine. Level of alcohol, sugars etc.

·       Adulteration

          The adulteration of wine is depend on the quality of grapes such as origin and variety. The wine is adulterated with chemicals, water, sweeteners and additives.

·       Microbial effect

           During fermentation of wine, the microbes change the matrix of by the production of organic and antimicrobial compounds. They use lactic acid bacteria in fermentation wine to convert malic acid into lactic acid that improves acidity and flavor of wine. However, they do not know that the lactic acid bacteria degrade the acidity of wine.

Coffee:     

Texture

            The texture of coffee is affected by roasting of coffee beans. They become more brittle and losing their strength and toughness because of chemical, physical and structural changes. Thickness of coffee is depend on the amount of dissolved and suspended solids.

·       Color

            The color of coffee is depend on the time of roasting. More will the time of roasting; more will be the darker color of coffee. Because during roasting, sugars covert to caramel by burning that give dark color.

·       Odor

             More than 800 compounds are produce during roasting. There are thermal degradation reactions that decompose proteins and sugars to volatile compounds, which imparts odor.

·       Taste

              The factors that effect on the taste of coffee are processing, brewing, environment and roasting. The taste also depend on the methods of brewing. The taste of coffee determine by the freshness of crop, type of packaging, and storage before and after roasting.

·       Nutritional composition

             The caffeine that are present in coffee inhibit the vitamins absorption. There have many health issues of coffee.

·       Adulteration

              Coffee is adulterated with roasted grains such as barley, oat etc. because they are cheap and their chemical and organoleptic composition do not affect the coffee.

·       Microbial effect

               There are some microorganisms such as bacteria and yeast that are used in the fermentation of coffee by degrading mucilage that are producing though it such as enzymes, acids and alcohols.