Juliano Lemos Bicas

Bio-oxidation of Terpenes: An Approach for the Flavor Industry

The terpenes are secondary metabolites of plants that are produced, in part, as a defense against microorganisms and insects in addition to their pollinator-attractive properties.1 In mammals, terpenes contribute to stabilizing cell membranes, participate in metabolic pathways, and act as regulators in some enzymatic reactions.2 Members of this class of chemicals have carbon structures which can be decomposed into isoprene (C5H8) residues and are classified, based on the number of carbons in the molecule, as monoterpenes (ten carbons), sesquiterpenes (fifteen carbons), diterpenes (twenty carbons), triterpenes (thirty carbons), and tetraterpenes or carotenes (forty carbons).3 The simpler terpenes (monoand sesquiterpenes) are the major constituents of essential oils and are widely used in the perfumery industry, while diand triterpenes are less volatile and are obtained from plant gums and resins.4 Carotenes are synthesized by bacteria, algae, fungi, and green plants and comprise more than 600 known structures.5 The most important terpenes and their oxygenated derivates (terpenoids) cited in this study may be seen in Figures 1-3. Terpenes are a good starting material for the synthesis of many fine chemicals due to their similar carbon skeleton. R-(+)-Limonene (2), for example, is the most abundant monocyclic monoterpene in nature, and it represents more than 90% of the orange peel oil; thus, it is an inexpensive precursor.6,7 The oxygenated derivatives of limonene, e.g. carveol (24), carvone (25), perillyl alcohol (26), menthol (39), and R-terpineol (29), are recognized for their pleasant fragrances,8 and some of them also present bioactivity against certain types of tumor cells, not only preventing the formation or progression of cancer but also regressing existing malignant tumors.9,10 R-(6) and -pinene (7), in turn, are found in high concentrations in turpentine, a paper and pulp industry residue, and they are, therefore, also available in bulk at a low price. These bicyclic monoterpenes are used as a fragrance substance that is used to improve the odor of industrial products and are also precursors of important flavor compounds, such as terpineols, borneol (45), camphor (46), citronellol (11), geraniol (14), menthol (39), verbenol (48), and verbenone (49).6,7 The tetraterpene -carotene (62), an orange pigment found mainly in tropical vegetables, is a precursor of norisoprenoid ionones, molecules responsible for desirable fruity and floral flavors.7,11 Volatile carotenoid breakdown products have been long known as important flavor compounds.12

Isolation and screening of d-limonene-resistant microorganisms

This study reports the isolation of microorganisms that are resistant to environment containing limonene, the most important residue in the citrus industry. For the isolation, samples collected from strategic places of a citrus processing plant (yellow water, entrance and exit of the bagasse tank, effluent and deteriorated fruits found in bins, machine straps, fruit washers and plant floor), some citrus fruit and mint from local market were used. The samples were incubated in rotary shaker at 30oC/150rpm for 48h or 7 days in YM medium containing 0.1% limonene. Great part of the 112 strains recovered after 48h and the 126 strains recovered after 7 days were identified as Gram positive bacilli, followed by Gram negative bacilli, yeasts and Gram positive cocci, besides five fungi. About half of the Gram positive and Gram negative bacilli and yeasts and some Gram positive Cocci were resistant to limonene concentrations up to 2% in the medium broth. Amongst them seventy were able to grow in mineral medium containing limonene as sole carbon source. The research described in this paper is the initial step for the exploration of flavor compounds production via biotransformation of limonene, a non-expensive by-product of citrus industry.

Comparative study of the bioconversion process using R-(+)- and S-(-)-limonene as substrates for Fusarium oxysporum 152B.

This study compared the bioconversion process of S-(-)-limonene into limonene-1,2-diol with the already established biotransformation of R-(+)-limonene into α-terpineol using the same biocatalyst in both processes, Fusarium oxysporum 152B. The bioconversion of the S-(-)-isomer was tested on cell permeabilisation under anaerobic conditions and using a biphasic system. When submitted to permeabilisation trials, this biocatalyst has shown a relatively high resistance; still, no production of limonene-1,2-diol and a loss of activity of the biocatalyst were observed after intense cell treatment, indicating a complete loss of cell viability. Furthermore, the results showed that this process can be characterised as an aerobic system that was catalysed by limonene-1,2-epoxide hydrolase, had an intracellular nature and was cofactor-dependent because the final product was not detected by an anaerobic process. Finally, this is the first report to characterise the bioconversion of R-(+)- and S-(-)-limonene by cellular detoxification using ultra-structural analysis.

Natural flavourings from biotechnology for foods and beverages

Abstract: Natural flavor compounds obtained by biotechnological processes are playing an increasing role in the food, cosmetic, chemical and pharmaceutical industries due to increasing consumer demand for natural food additives. There has been extensive research into the biotechnological production of flavor compounds during the past decade. Biotechnological production is a particularly attractive alternative for flavor production since it occurs under mild conditions, presents high regio- and enantio-selectivity, does not generate toxic wastes and produces products that may be labeled as ‘natural’. The biotechnological production of aroma compounds may be performed in two basic ways: through de novo synthesis or by biotransformation. De novo synthesis refers to the production of complex substances from simple molecules through complex metabolic pathways. Biotransformations are single reactions catalyzed enzymatically to result in a product structurally similar to the substrate molecule. This chapter describes the main groups of flavoring compounds obtained by both methods.

Interplay between food and gut microbiota in health and disease

Numerous microorganisms colonize the human gastrointestinal tract playing pivotal roles in relation to digestion and absorption of dietary components. They biotransform food components and produce metabolites, which in combination with food components shape and modulate the host immune system and metabolic responses. Reciprocally, the diet modulates the composition and functional capacity of the gut microbiota, which subsequently influence host biochemical processes establishing a system of mutual interaction and inter-dependency. Macronutrients, fibers, as well as polyphenols and prebiotics are strong drivers shaping the composition of the gut microbiota. Especially, short-chain fatty acids produced from ingested fibers and tryptophan metabolites are key in modulating host immune responses. Since reciprocal interactions between diet, host, and microbiota are personal, understanding this complex network of interactions calls for novel use of large datasets and the implementation of machine learning algorithms and artificial intelligence. In this review, we aim to provide a base for future investigations of how interactions between food components and gut microbiota may influence or even determine human health and disease.

Iridoid blue-based pigments of Genipa americana L. (Rubiaceae) extract: influence of pH and temperature on color stability and antioxidant capacity during in vitro simulated digestion

Iridoid blue-based pigments (IBBP) extract of Genipa americana L. represents a natural alternative additive for food applications and also exerts desirable biological effects on human health. In this study the iridoids present in the extract were identified, the influence of pH and temperature on color difference (ΔE) of IBBP was evaluated using a central composite design (CCD) and finally the antioxidant capacity was monitored before and after its in vitro digestion. Ten glucoside iridoids were detected and the main compounds identified were genipin, genipin 1-β-gentiobioside and geniposide. It was also observed an increase of 17-18% of antioxidant capacity after the in vitro digestion, respectively. Among the conditions tested, the color of extract was more stable at 12-20 °C and low pH (3.0-4.0), suggesting that it is compatible for coloring acidic foods. Finally, the in vitro digestion also increased the antioxidant capacity (ORAC assay) by 39%.

CHAPTER 12:Production of Aroma Compounds by White Biotechnology

Industrially, flavors and fragrances have wide applications in the food, feed, cosmetics, chemical and pharmaceutical sectors and have a global market estimated at billions (109) of dollars. In this respect, the biotechnological production of aroma compounds has emerged as an attractive alternative since it occurs under mild conditions, presents high regio- and enantio-selectivity, does not generate toxic waste, and the products obtained may be labeled as “natural”. Some problems related to these processes impact their final yield, making some of these bioprocesses not feasible for industrial applications to enable commercial application of most published processes. Nevertheless, the progress observed recently in this field has resulted in studies reporting satisfactory yields (on the order of grams per liter), which have potential applications on industrial scale. This chapter is intended to cover the main examples already reported for the production of aroma compounds through biotransformation, the main strategy compatible with industrial scale. Also, strategies from the “Green Chemistry” toolbox with potential applications in (bio)aroma technology will be presented.