Tema 12. Biotransformación. Introducción. Tipos de reacciones de biotransformación. Procesos industriales de biotransformación. Ejemplos y aplicaciones . Perspectivas de futuro. Tema 13. Vitaminas y aditivos . Acido Ascórbico. Vitamina B12. Riboflavina. beta-caroteno. Saborizantes. Edulcorantes. Intensificadores del sabor. Aromatizantes. Colorantes. Perspectivas futuras.

VITAMINASVitamina CVitamina B12

Vitamina C

Coenzima en reacciones de hidroxilación (sintesis de colágeno)

Reduce Fe3+ de la dieta a Fe2+ en el intestino (deficit anemia)

Antioxidante

Escorbuto

Vitamina B12

Transportados de grupos metilo. Es coenzima para:Metilmalonil CoA mutasa (degradación ácidos grasos de cadena impar) y, Homocisteina metiltransferasa (síntesis de metionina)

Anemia perniciosa: anticuerpos contra células parietales gástricas impidiendo la produccion del factor intrínseco (receptor de la vitamina). Este complejo viaja hasta el Ileon terminal y se une a los receptores del factor intrinseco de las células mucosas gástricas.

HORMONAS ESTEROIDEAS

AROMAS

Cesped

QUESO

ASADO

MELOCOTÓN

CEREZA

ALDEHIDOSVainillaBenzaldehido

Vanilla es un género de orquídeas con 110 especies distribuidas mundialmente en las regiones tropicales. La mejor conocida es la especieVanilla planifolia que produce un fruto del que se obtiene un saborizante, la vainilla. Es una especia del continente americano. Los conquistadores españoles de México, conocieron esta especie en las costas de Veracruz, le pusieron ese nombre porque su fruto se parece a la vaina de una espada pero diminuta, similar a las judías verdes

VAINILLA

Corynebacterium y Serratia

Pseudomonas putida (ATCC 55012)Benzaldehido es tóxico, mutante en benzoilformato descarboxilasa

Benzaldehido

(olor a cereza)

Picea ó abetos

DERIVADOS DE ÁCIDOS GRASOS Metilcetonasγ-decalactonas

Odor Type :cheesyOdor :Cheese, fruity, ketonic, green banana, with a creamy nuanceTaste :Cheese, fruity, coconut, waxy, green

2-Heptanona

Bioconversion of copra oil (aceite de coco) by two strains of Penicillium roqueforti spores was studied in the presence or absence of exogenous lipase. Without exogenous lipase action, methyl ketone productivities were weak: 33 +/- 1.9 to 61 +/- 2.4 micromoles g-1 of oil, respectively, for strains 1 and 2. This formation results from the bioconversion of free fatty acids present in copra oil and appears strain-dependent. The major ketone was 2-undecanone, reflecting the high concentration of dodecanoic acid in the substrate. After lipolysis of copra oil by a Candida cylindracea lipase, a large increase of methyl ketone productivities (912 +/- 13 and 1935 +/- 26 micromoles g-1 of oil, respectively) is noticed with 2-heptanone predominating. When the reaction time was increased, the amount of methyl ketones decreased and other volatile compounds were formed.

γ-decalactona

Decalactone is an aroma compound present naturally inmany fruits and fermented products. It is particularly importantin the formulation of peach, apricot, and strawberry flavors.Microbial processes to produce this compound have beenpatented, although the metabolic pathways involved arenot yet completely defined. Yeasts are used for industrialproduction, but the yields of this biotransformation commonlyare poor, rarely reaching concentrations over 4 to 5 g/liter offermentation broth

 Ricinus communis, que contiene aproximadamente un 40-50 % del aceite. El aceite a su vez contiene el 70-77 % de los triglicéridos del ácido ricinoleico.

TERPENOSMentolAlfa-Pineno

Menta

MENTOL

TIMOL

α-pineno es un subproducto de la pulpa de las coníferas

Limón/madera

Pseudomonas fluorescens NCIMB 11671

PIRAZINAS

PyrazinesPyrazines are heterocyclic, nitrogen-containing compounds which possess a nutty and roasted flavour. Theyare normally formed during conventional cooking/roasting of food through the Maillard reaction. Nowadays, the use of cooking processes that do not favourpyrazine formation (i.e. microwave cooking) has causedthe need to supply natural pyrazines with a roasty flavour as food additives. A few microorganisms are alsoable to synthesize pyrazines. For instance, bacteria suchas Corynebacterium glutamicum produce important quantities of tetramethylpyrazine from amino acids.

COLORANTES

Carotenoides

Annatto is a yellow/orange colorant that is widelyused in the food industry, particularly in the dairyindustry. Annatto, consisting of the carotenoids bixinand norbixin, is most commonly added to produce orangecheese, such as Cheddar, to achieve a consistentcolor over seasonal changes. This colorant is not allretained in the cheese, and thus a percentage remainsin the whey, which is highly undesirable. As a result,whey is often bleached. Hydrogen peroxide and benzoylperoxide are the 2 bleaching agents currently approvedfor bleaching whey in the United States. Recent studieshave highlighted the negative effect of bleaching onwhey flavor while concurrently there is a dearth of currentstudies on bleaching conditions and efficacy. Recentinternational mandates have placed additional concernon the use of benzoyl peroxide as a bleaching agent.