Food Chemistry II PDF

FCH 307/307L FOOD CHEMISTRY II KRISTAN DIANE B. CANTA, MSc., PFT  FLAVOR AND AROMATIC COMPOUNDS FOOD CHEMISTRY II Food Technology Kristan Diane B. Canta, MSc. PFT FLAVOR The sensation produced by a material taken in the mout...

FCH 307/307L FOOD CHEMISTRY II KRISTAN DIANE B. CANTA, MSc., PFT  FLAVOR AND AROMATIC COMPOUNDS FOOD CHEMISTRY II Food Technology Kristan Diane B. Canta, MSc. PFT FLAVOR The sensation produced by a material taken in the mouth, perceived principally by the senses of taste and smell, and also by the general pain, tactile and temperature receptors in the mouth. Denotes the sum of the characteristics of the material which produce that sensation. Edible chemicals and extracts that alter the flavor of food and food products through the sense of smell. In simple terms, flavor is the interaction between taste and aroma. Aroma is the main determinant of food’s flavor. FLAVOR CHEMISTRY Caused by receptors in the mouth and nose detecting chemicals found within the food. Receptors respond by producing signals that are interpreted by the brain as sensations of taste and aroma. One flavor may contain hundreds or thousands of component substances Image source: https://veritaswines.com/sparkling-wine-saga-part-1-witnessing-sparkling-scintilla-special/ Taste Perception Substances responsible for these aspects of flavor perception are water soluble and relatively nonvolatile. As a general rule, they are also present at higher concentrations in foods than those responsible for aromas, and they have been often treated lightly in coverages of flavors. Five basic taste: Sour, salty, sweet, bitter and umami SOUR Acidic in nature, and thus contain at least one proton that is dissociable in aqueous systems. Involves the binding of protons (H+) ions Concentration is proportional to taste intensity among inorganic ions Organic ions are stronger than inorganic ions at the same concentration The acid strength in a solution does not appear to be the major determinant of the sour sensation A weak acid taste as the same as strong acid at the same concentration. Example: acetic acid, citric acid, tartaric acid, lactic acid SALTY Classic, clean salty taste is provided by sodium chloride (NaCl) Exhibit complex tastes usually described as consisting of psychological mixtures of classic sweet, bitter, sour, and salty perceptual components. NaCl is sweet 0.020M and salty at higher concentrations 0.050 M. Cations and anions Example: K, Ca and Mg salts, choline salt SALTY Cations cause the basic salty taste Sodium and lithium cations – produce only salty taste Potassium and other alkaline earth cations – produce a combination of both salty and bitter tastes. Anions modify salt tastes by inhibiting the tastes of cations Contribute tastes of their own. Impact the flavor of most foods Chloride anion is least inhibitory to the salty taste; does not contribute a taste Citrate anion is more inhibitory than orthophosphate anions; contributes less taste than the orthophosphate anion. SWEET OH groups because sugars molecules are dominated by this feature. Shallenberger and Acree first proposed the AH/B theory for the saporous (taste eliciting) unit common to all compounds that cause a sweet sensation. AH-B Theory - The proton donor was called the AH group, and the proton acceptor was called the B group. Hydroxyl group and oxygen atoms can serve either the AH or B function in a molecule. BITTER Closely related to sweetness from a molecular structure– receptor relationship. Bitter molecules appear to have a requirement for only one polar group and a hydrophobic group. Quinine is an alkaloid that is generally accepted as the standard for the bitter taste sensation. The detection threshold for quinine hydrochloride (IV) is about 10 ppm Less soluble in water Bitterness is an important flavor attribute of several other beverages consumed in large quantities, including coffee, cocoa, and tea. BITTER Caffeine moderately bitter at 150–200 ppm in water, and occurs in coffee, tea, and cola nuts. added in concentrations up to 200 ppm to soft cola beverages, and much of the caffeine employed for this purpose is obtained from extractions of green coffee beans that are carried out in the preparation of decaffeinated coffee. Theobromine - very similar to caffeine, and is present most notably in cocoa, bitterness. Humulone is the most abundant substance, and it is converted during wort boiling to isohumulone by an isomerization reaction These nonvolatile, bitter substances can generally be categorized as derivatives of humulone or lupulone known in the brewing industry Tannins - tea UMAMI Compounds eliciting this taste sensation have been utilized by humans to improve flavors since the inception of food cooking and preparation. monosodium l-glutamate (MSG; XIII) and inosine monophosphate were scientifically referred to this category Widely accepted as a basic taste response. Umami substances contribute a delicious, mouthwatering taste to foods Prominent and desirable in the flavors of vegetables, meats, poultry, fish, shellfish, and aged cheeses. Pungent substances A chemesthetic property exhibited by a number of compounds found in spices and vegetables that cause characteristic hot, sharp, and stinging sensations Chili peppers, black pepper, and ginger – not volatile and unless made airborne via aerosol droplets, exert their effects principally on oral tissues. Eugenol – active component responsible for the pungency of mustards, horseradish, vegetable radishes, watercress, onions, and the aromatic spice, clove volatile, and produce both pungency in the oral and nasal cavities as well as characteristic aromas. Pungent substances Capsaicinoids - vanillylamides of monocarboxylic acids with varying chain length and unsaturation found in Chili peppers (Capsicum sp.) Piperine – an amide, principal pungent compound in pepper. Gingerols – group of phenylalkyl ketones responsible for the pungency o fresh ginger. Cooling substances Chemesthetic sensation that occurs when certain chemicals contact the nasal or oral tissues and stimulate the nonspecific neural systems (e.g., trigeminal, etc.). Most associated with mint-like flavors, including peppermint, spearmint, and wintergreen. Menthol in the natural form is most commonly used in flavors. Camphor produces a distinctive odor in addition to a cooling sensation. Astringency A feeling-related phenomenon perceived as a dryness in the mouth along with a coarse puckering of the oral tissue. Results from the association of tannins or polyphenols with proteins in the saliva to form precipitates or aggregates. Often confused with bitterness and many polyphenols or tannins cause both astringent and bitter sensations Odor Perception The olfactory mechanism is both more complex and more sensitive than the process of gustation. Provide sensual pleasure (the odor of flowers and perfume) or threats from spoiled food or chemical dangers. One of our principal means to communicate with our environment. There are thousands of odors, and the sensitivity of the smell organ is about 10,000 times greater than that of the taste organ. Aroma Responsible for the odor of food items, otherwise called odorant, a chemical compound that has a smell or odor. Odorants are at least partially water solubility, have a sufficiently high vapor pressure, low polarity, some ability to dissolve in fat (lipophilicity), and surface activity Aroma substances are volatile compounds which are perceived by the odor receptor sites of the smell organ (the olfactory tissue of the nasal cavity). Play a significant role in the production of flavorants, which are used in the food service industry to flavor, improve and increase the appeal of their products. Can be found in food, wine, spices, fragrance oils, and essential oils. FLAVOR AND AROMA COMPOUNDS Image source: Sharma A, Sharma P, Singh J, Singh S and Nain L (2020) Prospecting the Potential of Agroresidues as Substrate for Microbial Flavor Production. Front. Sustain. Food Syst. 4:18. doi: 10.3389/fsufs.2020.00018 Osmophores - millions of compounds with odor known ALIPHATIC – straight chain compounds, usually fatty acids and their derivatives. Examples of which are diacetyl in margarine and methylamyl ketone in cheeses AROMATIC – contains benzene ring. Aromatic compounds provide sweet to woody to naphthalene odor. Examples of which is methyl salicylate (fresh green aroma) and salicaldehyde (bitter almond)  SULFUR AND NITROGEN Sulfur compounds are odorous and are more volatile. Nitrogen containing compounds are derived usually from browning reactions such as pyrazine in roasted coffee and tea.  ISOPRENOID DERIVATIVES – includes sesquiterpenes and terpenes. Sesquiterpenes - zingiberene found in turmeric. Monoterpenes - limonene – orange odor and flavor ALDEHYDES ALDEHYDES acetaldehyde (pungent), benzaldehyde (marzipan, almond), hexanal (green, grassy), cinnamaldehyde (cinnamon) citral (lemongrass, lemon oil), hexenal (green tomatoes), neral (citrus, lemongrass), vanillin (vanilla). KETONES used to add fruity flavors to products. ACIDS ALCOHOL give a characteristic aroma to food products. ALCOHOL benzyl alcohol (oxidizes to benzaldehyde, almond) ethyl maltol (cooked fruit) furaneol (strawberry) menthol (peppermint)  One of the most significant chemical groups that impart ESTERS a fruity, candy flavor and are used in fruit-flavored dairy products LACTONES Cyclic esters of gamma- and delta-hydroxy acids, which contribute a coconut-like, creamy, creamy, sweet, fruity, or nutty flavor. PYRAZINES Nitrogen-containing heterocyclic compounds that impart roasted and nutty flavors. AMINES Amines such as Cadaverine (rotting flesh), Indole (jasmine flowery), putrescine (rotting flesh), pyridine (very unpleasant), trimethylamine (fish) Flavorants or flavorings Alter or enhance the flavors of natural food products such as meats and vegetables. Create flavor for food products that do not have the desired flavors 3 types of flavoring: Natural flavoring Nature-identical Artificial Natural flavoring Obtained from plant or animal raw materials, by physical, microbiological or enzymatic processes. Can be used in their nature state or processed for consumption High cost and unavailable raw materials May contain toxins from their sources Methods of extraction include solvent extraction, distillation or physical forces. Nature identical Produced by chemical synthesis which are chemically identical to natural flavoring substances Lacks artificial flavoring substances Artificial Specific and complex mixtures of single naturally occurring flavor compounds combined together Safer to consume than natural flavors More pure and undergo more testing Most of the flavorants are esters. Flavor enhancers Amino acids or nucleotide derivatives that capable of enhancing the odor of food Referred to as savory flavorants or umami. Manufactured as sodium or calcium salts. Flavor enhancers: 1. Glutamic acid salts – Sodium salt of glutamic acid is called monosodium glutamate (MSG), one of the most commonly used flavor enhancers in food processing. 2. Glycine salts – A simple amino acid that is usually used in conjunction with glutamic acid as flavor enhancers. 3. Guanylic acid salts – Nucleotide salts that are usually used in conjunction with glutamic acid as flavor enhancers. 4. Inosinic acid salts – Nucleotide salts created from the breakdown of AMP. Due to high costs of production, it is usually used in conjunction with glutamic acid as flavor enhancer. Flavor enhancers: 5. Organic acids – Organic acid are usually not considered and regulated as flavorants by law. But they can impart different sour or taste that alters the flavor of a food Acetic acid – It gives vinegar sour taste and distinctive smell Citric acid – It is found in citrus fruits and gives them their sour taste Lactic acid – It is found in various milk products and give them a rich tartness Malic acid – It is found in apples and gives them their sour or tart taste Tartaric acid – It is present in grapes and wines and gives them a tart taste FLAVOR INTERACTION MOISTURE Affects the rate of release of flavor compound LIPIDS Increase flavor retention CARBOHYDRATES Stabilize flavor compounds PROTEIN Flavor compounds are retained STABILITY OF FLAVORS All initial flavors depletes with time Certain off-flavor compounds increases with time Thermal processing accelerates loss of flavor compounds BREAD Flavor The flavor of white bread is formed mainly from the fermentation and baking processes. Loss of flavor is the result of disappearance of volatile flavor components. Aroma Cooling and storage – aroma is lost Aroma is partially regenerated by simply heating the bread. During fermentation, a number of alcohols are formed, including ethanol, n- propanol, isoamyl and amyl alcohol etc. However, much of the alcohol is lost during baking During baking, the formation of the crust and browning appear to be primary contributors to bread flavor. The browning is mainly the result of a Maillard-type browning. This accounts for the presence of the carbonyl compounds, especially furfural, hydroxymethylfurfural, and other aldehydes. MEAT Flavor is developed by heating from precursors present in the meat; this occurs in a Maillard-type browning reaction. The overall flavor impression is the result of the presence of a large number of non- volatile compounds and the volatiles produced during heating. Meat extracts contain a large number of amino acids, peptides, nucleotides, acids, and sugars. The presence of relatively large amounts of inosine-5'-monophosphate has been the reason for considering this compound as a basic flavor component. In combination with other compounds, this nucleotide would be responsible for the meaty taste. The volatile compounds produced on heating can be accounted for by reactions involving amino acids and sugars present in meat extract. Lean beef, pork, and lamb are surprisingly similar in flavor; this reflects the similarity in composition of extracts in terms of amino acid and sugar components. FISH Fish contains sugars and amino acids that may be involved in Maillard-type reactions during heat processing (canning). Proline is a prominent amino acid in fish and may contribute to sweetness. The flavor of cooked, fresh fish is caused by the presence of sugars, including glucose and fructose, giving a sweet impression as well as umami component arising from the synergism between inosine monophosphate and free amino acids. The fresh flavor of fish is rapidly lost by bacterial spoil- age. In fresh fish, a small amount of free ammonia, which has a pH level of below seven, exists in protonated form. As spoilage increases, the pH rises, and ammonia is released. The main source of ammonia is trimethylamine, produced as a degradation product of trimethyl-amine oxide. MILK The flavor of normal fresh milk is probably produced by the cow’s metabolism and is comprised of free fatty acids, carbonyl compounds, alkanols, and sulfur compounds. Free fatty acids may result from the action of milk lipase or bacterial lipase. Lipids, proteins and lactose may be precursors of flavor compounds in milk. Sulfur compounds that can be formed by heat from β-lactoglobulin include dimethyl sulfide, hydro- gen sulfide, dimethyl disulfide, and methanethiol. The basic taste of milk is very bland, slightly sweet, and salty. Processing conditions influence flavor profiles. The extent of heat treatment determines the type of flavor produced. Low heat treatment produces traces of hydrogen sulfide. Ultra-high temperature treatment results in a slight fruity, ketone-like flavor. Sterilization results in strong ketone-like and caramelization/sterilization flavors. Sterilization flavors of milk are caused by the presence of 2-alkanones and heterocyclic compounds resulting from the Maillard reaction. Because of the bland flavor of milk, it is relatively easy for off-flavors to take over. CHEESE The flavor of cheese largely results from the fermentation process that is common to most varieties of cheese. Depending on the type of culture used and the duration of the ripening process, the cheese may vary in flavor from mild to extremely powerful. Casein, the main protein in cheese, is hydrolyzed in a pattern and at a rate that is characteristic for each type of cheese. Proteolytic enzymes produce a range of peptides of specific composition that are related to the specificity of the enzymes present. Bitter peptides may be formed contributing to off flavor. Carbonyls, esters, and sulfur compounds are included in this group.. Sulfur compounds found in cheese include hydrogen sulfide, dimethyl sulfide, methional, and methyl mercaptan. All of these compounds are derived from sulfur-containing amino acids. FRUITS The flavor of many fruits appears to be a combination of a delicate balance of sweet and sour taste and the odor of a number of volatile compounds. The characteristic flavor of citrus products is largely due to essential oils contained in the peel. The essential oil of citrus fruits contains a group of terpenes and sesquiterpenes and a group of oxygenated compounds. The volatile water-soluble constituents of orange juice consist mainly of acetaldehyde, ethanol, methanol, and acetic acid. As in the case of citrus fruits, no single compound is completely responsible for any single fruit aroma. Some organoleptically important compounds characteristic for particular fruits have been found. These include amyl esters in banana aroma, citral in lemon, and lactones in peaches. VEGETABLES Vegetables contain an extensive array of volatile flavor compounds, either in original form or produced by enzyme action from precursors. Onion and garlic have distinctive and pungent aromas that result mostly from the presence of sulfur- containing compounds. A large number of flavor compounds in vegetables are formed after cooking or frying. In raw onions, an important compound is thiopropanal s-oxide—the lachrymatory factor. The distinctive odor of freshly cut onions involves two main compounds: propyl methane- thiosulfonate and propyl propanethiosulfonate. Raw garlic contains virtually exclusively sulfur compounds: four thiols, three sulfides, seven disulfides, three trisulfides, and six dialkylthio-sulfinates. TEA The flavor of black tea is the result of a number of compounds formed during the processing of green tea leaves. The distinctive flavor of tea is due to its content of lactones, aldehydes, alcohols, acids, and pyridines. COFFEE The flavor of coffee is developed during the roasting of the green coffee bean. Recent studies have identified 655 compounds in the flavor of coffee, the principal ones being furans, pyrazines, pyrroles, and ketones. The distinctiveness of coffee flavor is related to the fact that it contains a large percentage of thiophenes, furans, pyrroles, as well as oxazoles, thiazoles, and phenols. ALCOHOLIC BEVERAGES In distilled beverages, one of the major flavor compounds is acetaldehyde. Acetaldehyde represents about 90% of the total aldehydes present in beverages like whiskey, cognac, and rum. Together with other short-chain aliphatic aldehydes, it produces a pungent odor and sharp flavor, which is masked by other flavor components in cognac, fruit brandies, rum, and whiskey. E-Nose / E-Tongue Device intended to detect odors or flavors The name comes from e-sensing These devices take data and transform it into more comprehensible sensory information, imitating the capabilities of their human counterparts. There’s an e-nose patented by UST DOST has e-sensing technology References: Belitz HD and Grosch W. 2005. Food Chemistry. 4th ed. Heidelberg, Germany. Springer- Verlag Berlin Heidelberg Coultate TP. 2009. Food: The Chemistry of its Components, 5" ed. Cambridge: Royal Society of Chemistry Cui SW (ed), 2005. Food Carbohydrates: Chemistry, Physical Properties, and Applications. Boca Raton, FL: CRC Press, Taylor and Francis Group. Damodaran S and Parkin KL (eds). 2017. Fennema's Food Chemistry, 5" ed. Boca Raton, FL. CRC Press, Taylor & Francis Group. De Man JM. 2003. Principles of Food Chemistry. Gaithersburg, Md. Aspen Publishers, Inc. Eskin NAM and Shahidi F (eds). 2013. Biochemistry of Foods, 3" ed. London: Academic Press, an imprint of Elsevier Inc. Fennema OR. 1996. Food Chemistry. New York, New York. Marcel Dekker. Hui YH. 2006. Food Biochemistry and Food Processing Ames, IA: Blackwell Publishing Learning activity #2: Submission: OCTOBER 30, 2024 List down important flavor compounds from the following foods: Banana Apple Lemon Vanilla Cinnamon Pepper Turmeric Anise Coffee Cumin