IE47697B1 - Cocoa flavored product and process for manufacturing same - Google Patents

Abstract

A roasted yeast product having the characteristic texture, color, flavor, aroma and mouth-feel of cocoa powder is produced by roasting a food yeast at a temperature of about 100`C. to about 300`C. for about 1 to about 50 minutes. The product may be used as a cocoa extender, substitute or replacer in foodstuffs employing cocoa and/or chocolate.

Description

This invention relates to a product having cocoa-like flavor notes, and more particularly to a roasted yeast product which may be used as a cocoa extender, substitute and/or replacer and to methods of manufacture thereof.

Cocoa powder and chocolate are utilized extensively as 10 consumable foodstuffs in a wide variety of applications, including use as a beverage base, and as a flavoring ingredient in formulated drinks, ice cream, cakes and biscuits, icings and confectionery coatings, confectioneries and the like.

Both cocoa powder and chocolate are derived from cocoa beans which are grown only in tropical and semi-tropical climates. Most of the world's cocoa beans are grown in West Africa, Brazil, Trinidad, Ecuador, Venezuela and Java. Since the cocoa bean is a natural agricultural product, the world supply of cocoa powder and chocolate is dependent, upon varying and often unpredictable weather conditions. In addition, the major cocoa powder and chocolate consuming areas of the world must import cocoa beans, thereby making cocoa powdpf and:chocolate relatively expensive foodstuffs.

For these and other reasons, attempts have been made in the past to produce products which may be substituted for cocoa powder or chocolate, or which may be used to extend cocoa ' - powder1 or ohccoiate and thereby reduce reliance upon natural cocoa beans. Such cocoa powder or chocolate substitutes or extenders ideally approximate the color, flavor, aroma and mouth-feel or texture of cocoa powder or chocolate. However, since cocoa ir; a complex natural product comprising carbohydrate, fats, proteins, mineral matter, theobromine, caffeine, rater and fibre, substitutes or extenders approximating ail of the properties of cocoa powder or chocolate are difficult to obtain.

Prior cocoa powder nnd chocolate substitutes and extenders include processed carob, roasLcri defatted wheat germ,' and other processed cereal products. In addition. s U.K Patent Specification No.'925072 United States Patent No. 3,102,816 of Green et al./discloses a process for producing a beverage flavor from yeast and sugar, for use in association with other flavor factors such as bitterness, astringency, aroma and the like to resemble a natural beverage flavor, by forming a hydrous reaction mixture of a yeast and a reducing saccharide containing at least 10% moisture and preferably two parts water to one part solids, heating the mixture to at least 350°F. in a closed reaction vessel to obtain a headspace pressure of 75 to 225 p.s.i.g. over the normal pressure for saturated steam af the reaction temperature and then rapidly reducing the temperature of the reaction mixture to below 250!'’. The foregoing process, however, produces a product which must be used in association with other flavor factors to resemble a natural product, requires the presence of a reducing saccharide in tlie reaction mixture, requires a relatively high level of energy input nnd requires ε relatively large level of capital equipment expenditure in order to conduct the process.

In accordance with the present invention, a product having the characteristic texture, color, taste, arom.i and mouth-feel of powdered cocoa is obtained by roasting edible yeast at a temperature of 200°C to 250°C for a sufficient period, of time to develop the colour, flavour and aroma of natural cocoa. The resulting product may he substituted entirely for cocoa powder as a replacer without the addition of other flavour factors in common cocoa powder or chocolate uses, or can he used as an extender for -cocoa in a foodstuffs formulation.

DESCBIPTIOH OF ILLUSTRATIVE EMBODIMENTS OF THE INVENTION As used herein, the term yeast is intended to mean fungi whose usual and dominant form is unicellular. Yeasts useful with the present invention include any yeasts and mixtures of yeasts which are suitable for human consumption, and preferably those yeasts which are generally classified as food yeasts. Illustrative examples of such yeasts include, hut are not limited to, yeasts of the Saccharomyces, Candida and Brettanomyces genera, sueh as, for example, yeasts of the species Saccharomyces carlsbergensis (Saccharomyces uvarum), Saccharonyces cerevisiae, Saccharomyces fragilis, Candida utilis (Syn. Torulopsis utilis, ver. Torrela) and Candida tropicalis. Those yeasts popularly known as brewers .yeast, bakers yeast and wine yeast are included in the foregoing classification, and due to commercial availability are particularly preferred in the practice of the invention. Although the propagation history of the yeast is not limiting to the scope of the inventive concepts, it has been found that particularly good cocoa and/or chocolate colour, flavour and aroma characteristics are obtained from yeast which have been 7 6 9 7 propagated in a hopped substrate or a substrate comprising hop It is, therefore, a further particularly preferred practice to utilize yeast which has been recovered from a hopped brevier's wort fermentation in a conventional commercial malt beverage fermentation process, as will be hereinafter further explained,'or yeast which has been propagated on a synthetic medium containing hops or hop fractions, such as acids, resins, oils, tannins and gums. However, a suitable product may be obtained from yeast having no prior association with brewer's wort, hops or hop fractions.

The terms roast or “roasting as used herein mean to heat by exposure to a dry heat source such as by exposure to radiant heat energy or to a suitable medium, such as air, having an elevated temperature level and a relatively low moisture content. These terms do not include heating in the presence of a substantial amount of wet heat sources such as by steam heating, or to the utilization of abnormally or artificially high pressure levels. Those yeasts having a moisture content greater than about 5% by weight are dried prior to roasting, as hereinafter described, either as a separate step, or as the result of application of dry heat during roasting of the yeast.

In producing the product of the invention, yeast i.s roasted by heating the yeast to a sufficient temperature and for a sufficient time to develop desired texture, color, flavor and aroma characteristics and intensities. Optimum roasting temperatures and times are dependent upon the characteristics of the particular yeast or mixture of yeasts to be treated and the particular texture, color, flavor and aroma characteristics desired. However, for most purposes, it has been found that desirable texture, color, flavor and •17 69 7 aroma characteristics arc obtained by roasting the yeast at During roasting, the yeast undergoes chemical reactions to a degree dependent upon the roasting temperature and time, resulting in an increase in intensity and development of yeast color, flavor and aroma. The yeast is roasted at a sufficienttemperature for a sufficient time to obtain a roasted yeasst product having the characteristic texture, color, flavor and aroma of cocoa.

Yeast roasting may be accomplished by heating the yc-ast in or on a suitable supporting or transporting container, bed, cylinder or the like adapted to uniformly heat and roast the yeast. Roasting may be performed on a batchwise basis or continuously such as, for example, by passing a uniform layer of yeast on a continuous belt or other flat surface through an elongated oven. Means are preferably provided for ensuring uniform roasting of the yeast, such as means for mixing the layer of yeast on the belt during roasting. Alternatively, roasting may be accomplished by dispersing the yeast into a column of concurrent or countercurrent heated air flow, or by other suitable means.

If the yeast to be roasted as set forth herein contains a moisture content, greater than about 5't by weight, then the yeast is treated prior to roasting by drying tiie yeast to a moisture content less than about 5%, more preferably less than about 2.5% and most preferably less than about l.Oi- by weight. Yeast drying may bo accomplished separately from roasting by means of heat and agitation alone as in a drum dryer, by moans of spraying the yeast into a spray dryer employing a counter current or concurrent flow of heated air, by means of heated or unheated vacuum systems,.or the like. When drying,is employed as a separate step prior to roasting by utilization of heat, drying is preferably performed under such conditions as to avoid pyrolysis of the yeast. Spray drying is a particularly preferred means of yeast drying since it is particularly adapted to rigid process control, high yield and maintenance of a uniform dry yeast particle size. Yeast drying may also be accomplished during heating of the yeast for roasting, since actual roasting of the yeast does not occur until after the moisture content of the yeast has been reduced below about % by weight. However, it has been found that it is difficult to avoid yeast clumping and to obtain uniform roasting when drying is accomplished during the roasting step. It is therefore a ireferred practice to carry out yeast drying as a separate step prior to roasting. Yeasts having very high moisture contents, such as aqueous yeast dispersions or slurries, yeast recovered from a brewers wort fermentation or other liquid yeast mixtures, are initially preferably subjected to one or more suitable yeast separation techniques, such as centrifugation, filtration or the like, and then dried as heretofore set forth. Although it is preferred to carry out yeast drying prior to roasting, drying and roasting may be combined with each other in any degree of association ranging from simultaneous single unit processing to tandem or separate processing.

Duo to the commercial availability of brewers yeast as a by-product of commercial brewoi'y operations and the unique chemical composition of brewers yeast, brewers yeast recovered from a malt beverage fermentation process is a preferred source of yeast for processing according to the invention. Various types of yeasts are commonly encountered in malt beverage production. Yeasts separating cleanly and efficiently from the malt beverage in the terminal stages of fermentation are generally known as flocculent yeasts.

These yeasts respond readily to brewing practices and are easily recoverable for treatment as herein described.

. Yeasts generally known as powdery yeasts are less readily managed in brewing practices following fermentation. However, some brewers prefer powdery yeasts to insure prolonged relatively high yeast cell density for secondary fermentation, minor product synthesis and/or flavor maturation. Flocculent yeasts, powdery yeasts and ale yeasts, and yeast collected from any stage of a brewing process, may be used as a yeast source for treatment as heroin disclosed.

Common malt beverage fermentations yield from about 3 to about 5 kilograms of yeast for each kilogram originally innoculated into the wort. When bottom fermenting yeasts, such as Saccharomyces carlsborgensis (Saccharomyces uvarum), are employed in the wort, the yeast crop settles on the bottom of the fermentation vessel together with a variety of precipitated materials accummulated throughout the residence time of the malt beverage in the fermentation vessel to form a dense composition hereinafter referred to as yeast crop and inclusions, or simply yeast crop. The yeast crop comprises, for example, yeast cells in all stages of viability, the so called cold break consisting of proteins, protein30 polyphenol complexes, tannins, carbohydrates, hop fractions 47,697 and various .inclusion solids originating in tho basic brewing materials, .>11 of which are dinporned in a residua) entrapped malt beverage liquid. This complex yeast crop accummulates on tlie bottom of the fermentation vessel becoming an increasingly thick, heavy, pasty heterogeneous mass as the fermentation process progresses, while the supernatant malt beverage becomes relatively clear with relative]y low yeast densities when fully attenuated. However, those beverages designed for secondary fermentation may contain by design relatively heavy suspended yeast densities in excess of 2,000,000 yeast cells per milliliter.

For example, i.n order to recover a yeast crop from a malt beverage bottom fermentation process for use in the present invention, the supernatant malt beverage is decanted from the yeast crop and a sufficient quantity of the yeast crop is isolated for subsequent inoculation of process wort or for continuing the culture propagator. Xn tlie case of a top fermenting yeast, such as an ale yeast, the yeast crop is skimmed from the top of the supernatant malt beverage in a conventional manner. The remainder of the yeast crop is then preferably separated from the entrained residual malt beverage by physical separation means such as centrifugation, filtration or the like, with the recovered malt beverage being returned to the beverage production process. The recovered yeast crop, now having the physical form of a dense yeast paste, is further treated as follows to obtain yeast for roasting.

Due to the potential inclusion of hop residues and other extraneous material in the recovered yeast crop, the yeast crop is preferably subjected to a washing treatment by suspending or mixing the yeast into an aqueous solution of a suitable yeast washing agent to form a yeast slurry. Suitable yeast washing agents include the hydroxides, carbonates and bicarbonates of the alkali metals and the alkaline earth metals, including,' without limitation, those compounds yielding in solution a cation selected from the group consistin' of sodium, calcium, potassium and mixtures thereof and an anion selected from tlie group consisting of hydroxide;, carbonate and bicarbonate and mixtures thereof. The limited solubility of CaO in water, i.e. about a 185 mg CaO/lOO g HgO at 0°C, provides a convenient means of controlling the nature and concentration of the aqueous solution of the yeast washing agent. Therefore, a particularly preferred solution for this purpose is a saturated slaked lime or lime water solution having a calcium hydroxide concentration of approximately' 1500 ppm. The yeast slurry is preferably formed by suspending or mixing about one part of the recovered yeast crop paste with about one part of tho aqueous solution of yeast washing agent and then adding sufficient additional aqueous solution to adjust the pH of the slurry as desired. The pH of the slurry may be greater than about 6.0, more preferably about 6.0 to about 8.0, and most preferably about 6.5 to about 6.7. Suspending or mixing the yeast crop in a slightly acidic, neutral or slightly alkaline solution facillitates removal of a significant portion of soluble and insoluble materials associated with the yeast crop upon subsequent separation of the yeast crop from the solution. Suspending or mixing the yeast crop in a relatively higher pH alkaline solution, may additionally result in debittoring of the yeast crop.

The yeast, slurry is additionally preferably screened such as by passing the slurry through a fine mesh seioon, & 47697 having a mesh size sufficient to allow passage of yeast cells therethrough, of, e.g., about 100 mesh Tyler, to remove gross precipitates and various inclusion products of tiie brewing process. Alternatively, the yeast crop may bo subjected to screening prior to initial centrifugation and separation of entrained malt beverage in the yeast crop, or at other stages of the process.

The yeast is separated from the yeast slurry by use of physical separation means such as centrifugation, filtration or tht* like, to concentrate the yeast crop and remove therefrom a substantial portion of the yeast washing agent. The yeast I may then be dried and roasted as heretofore described to form the roasted yeast product.

When yeast has been dispersed in an aqueous solution of a yeast washing agent, as previously described, it may additionally be desirable to remove all or a substantial portion of any yeast washing agent remaining associated with the yeast. Such removal may be accomplished by eluting the yeast in water or other suitable solvent, and may be performed at any point in the process subsequent to yeast washing.

Optionally, the “live yeast recovered from a commercial brewing process may be deactivated prior to drying the yeast. Yeast deactivation may be accomplished, for example, by heating the yeast to a temperature of about 55°C to about 100°C for a minimum time of about one minute.

It is contemplated that brewers yeast recovered from a fermentation vessel may be separated from entrained malt beverage, and then directly dryed and roasted without washing, screening and eluting, as previously described.

It.iis further contemplated that the roasted yeast product of the invention may be comminuted, either prior to roasting, subsequent to roasting or both, to obtain a roasted yeast product having a desired average particle size for a particular end use. Preferably, the roasted yeast product is comminuted to an average particle size of cocoa powder, such as, for example, about 99% through 200 mesh Tyler to about 99% through 325 mesh Tyler.

The roasted yeast product as previously described is in the form of a powder and has the characteristic texture, color, aroma and flavor of cocoa powder, can be comminuted to the particle size of ground cocoa powder, and may be directly substituted for any part of, or to the total exclusion of, cocoa powder in foodstuffs utilizing cocoa and/or chocolate, such as beverages, baked goods, dairy products, candies, confections, coatings, syrups and the like. In ad15 dition, the roasted yeast product does not contain the theobromine or caffein of cocoa powder and may be utilized by those who are unable, or prefer not, to ingest these alkaloids.

The following illustrative examples show some of the conditions under which the roasted yeast product of the in20 vention may be employed and some of the variety of edible foodstuffs in which the product may be substituted for cocoa powder. These examples are presented for purposes of illustration only and are not intended to limit in any manner the yeasts, process conditions or potential uses of the method and product of the invention.

Example I A brewers' bottom fermenting yeast, Saccharomyces carlsbergenis, var. Frohberg (Saccharomyces uvarum), is collected routinely from a commercial beer fermentation 47697 , process following a normal, vigorous, single closed vessel primary beer fermentation.

The yeast is centrifuged to separate entrained beer from the yeast and suspended solids. The yeast is slurried into water to form a suspension of approximately 30¾ solids and is then spray dried in a commercial counter-current hot air drier to yield a finely powdered dry yeast material of about 5% by weight moisture content. The percentage composition by weight of the dried yeast is shown approximately in Table 1.

TABLE I Dried Yeast Composition Before Roasting After Roasting Protein 45% 44% Fat 2% 1% Carbohydrate 40% 43% Fiber 1% 4% Ash 7% 7% Moisture 5% 1% Note that the yeast is not washed, •debittered or treated in any manner to alter the cells, their absorbed materials or inclusion products.

The dried yeast powder mixture is then spread loosely onto a series of flat shallow pans; placed into a preattemperated, static hot air oven at 205°C (400°F); and allowed to roast at this temperature uninterrupted for a period of twenty minutes. During roasting, the yeast powder is periodically stirred to achieve uniform roasting. Prior to roasting, the dried yeast has a light beige color, is faintly aromatic, and is sharply and strongly bitter to taste. Following the roasting process the product has a distinct pleasant aroma and has developed a rich deep brown color best described as a chocolate color. The roasted product is removed from the oven and air cooled, while being protected throughout the process from accidental contamination.

A beverage is prepared from the roasted product to simulate hot cocoa or hot chocolate, as follows. A drink base is prepared according to the formula of Table II: TABLE II DRINK BASE COMPOSITION Sugar Granulated Fine 592 Non-Fat Dry Milk 300 Keltrol (Registered Trade Mark) 20 Salt 10 Vanilla P.F.W. 8 Imitation Cream Flavor P.F.W. 5 Beet Powder Fine Ground 5 Total Batch Weight 940 gms A 0.6 gm sample of the roasted yeast product is mixed with 9.4 gm of the drink base, and the combined product is stirred into 100 ml of boiling water. The resulting beverage has a characteristic hot cocoa (hot chocolate) appearance, aroma, flavor and general appeal. 4-7697 Example II The roasted, dried, non-debittered brewers yeast product prepared in Example I is used in the formulation of a designed substitute chocolate for confection, shown in Table III.

TABLE III Cocoa Butter 52.50 gm Roasted, Dried, Non-De- 15.00 gm bittered Brewers Yeast Powdered Sugar 10.00 gm Imitation Vanilla 3.00 gm Cream Flavor Veltol (Registered Trade Mark) 0.02 gm The roasted dried yeast product, the powdered sugar, 15 imitation vanilla cream flavor and the Veltol are intimately mixed together and set aside while the cocoa butter is melted to a smooth, free flowing liquid in the pan of a hot water double-boiler. Double—boiler heat and constant stirring are applied continuously to the fluid cocoa butter as the entire dry mixed ingredients of Table I are slowly added and homogeneously incorporated into the melt.

The product thus produced has a light brown color and a sweet pleasant aroma both resembling enrobing chocolate. The combined fluid product is poured into molds and allowed to set (harden) at room temperature to soft but firm solid bars. The product bars have the characteristic texture, appearance, aroma and flavor of chocolate enrobing bars and have been found to be an enjoyable confection.

Example III The roasted, dried, non-debittered brewers yeast product prepared in Example I is used in formulation of a cocoa substitute for baked goods, as shown in Table IV.

TABLE IV Baked Good Ingredients 887.85 gm sugar 81 gm buttermilk powder 325.8 gm butter 18 gm butter vanilla #218 144 gm egg 2-1/4 cup water 765.6 gm flour 3 gm baking soda 4.5 gm salt 15 160.5 gm roasted, dried non-debittered yeast The sugar, butter and egg are creamed together and the buttermilk powder, butter vanilla #218 and water are added to form a mixture. The flour, yeast product, baking soda, and salt are thoroughly intermixed and then added to the above mixture to form a dough-like composition that is dropped by the rounded teaspoon on a lightly greased pan.

The pan and contents are then placed in a preheated oven at 400 degrees F, for approximately eight minutes. The baked goods, which resemble ordinary chocolate cookies, are then removed from the oven and allowed to cool.

The resulting cookies have the characteristic flavor, texture, aroma and color of chocolate cookies.

Example IV A brewers bottom fermenting, non-debittered dried yeast is obtained from a source unrelated to the source of yeast employed in Examples I-III. This yeast is known to be of different culture and variation, and further known to be from a yeast crop of commercial beer fermentation employing entirely different wort media, brewing process and fermentation practices from that applied to the history of yeasts in Examples I-III.

This distinctly different non-debittered, dried brewers yeast is roasted according to the procedures outlined in Example I. The resultant product is, for all pertinent properties, identical to the product of Examples I.

A beverage prepared according to Example I with the substitution of the present yeast product has a pleasant, sweet cocoa aroma and flavor and has been found to be an acceptable cocoa flavored beverage.

Example V Following the procedure of Example I, a roasted, dried, non-debittered brewers ale yeast, Saccharomyces cerevisiae, is prepared from which a palatable, distinct cocoa beverage is prepared following description of said example.

Example VI A bakers yeast, Saccharomyces cerevisiae, whose history is believed to be unrelated to exposure to brewing processess and wort, is experimentally propagated in a wort and collected following a normal closed vessel primary fermentation.

The yeast slurry was centrifuged, spray dried, and roasted according to Example I. Following the roasting process, the product has the color, flavor, aroma and mouth-feel of natural cocoa.

The product is used to prepare a beverage as described 5 in Example I. The resulting beverage has notes of eoeoa flavor in the beverage, although the quality of the beverage is deemed inferior in chocolate flavor likeness to the beverage prepared in Example I.

Example Vll A yeast crop comprising a brewers bottom fermenting yeast, Saccharomyces carlsbergensis, var, Frohberg (Saecharomyoes uvarum) is collected routinely from a commercial beer fermentation process following a normal, vigorous, single closed vessel primary beer fermentation. The mixture is centrifuged to separate entrained beer from the yeast.

Immediately following centrifugal separation, the yeast crop is dispersed in a sufficient quantity of a saturated lime water solution to form a yeast slurry having a pH of 6.6. The yeast slurry is passed through a vibrating 100-mesh screen to remove debris and is then centrifuged to form a relatively thick yeast paste having a solids content of about 15% by weight. The yeast is then deactivated by 7697 heating the yeast in a wiped-film heat exchanger at a temperature of 75°C. for one minute. The deactivated yeast is then dried to a moisture content of about 1% by weight by spraying the yeast at the rate of 2 kg/hr. into a spray dryer having a countercurrent air flow at an inlet temperature of about 250eC. and an outlet temperature of about 100’C.

The dried yeast is spread uniformly to a depth of 1/4 inch onto a continuous belt and is then passed at a speed of 4.5 feet per minute through a band oven having a length of 15 feet, an ambient entrance temperature at the belt of about 23°C. and exit temperature at the belt of 238’C. The yeast is then allowed to cool to ambient temperature. Residual CaO and other soluble materials are then leached from the roasted yeast by suspending about one part by weight of roasted yeast in about 8 parts, by weight, of moderately hard potable water, mixing the suspension for 15 minutes, centrifuging the suspension to recover the roasted yeast and then drying the yeast to a moisture content of 5% by weight.

The roasted yeast product is substituted for the roasted yeast in Examples I, II and III. The foodstuffs so formulated have the characteristic texture, color, flavor, aroma and mouth-feel of corresponding foodstuffs formulated from cocoa ' powder.

Claims (6)

1. A method, of producing an edible yeast product, which ο θ comprises roasting the yeast at a temperature of 200 C to 250 C for a sufficient period of time to develop the colour, flavour and aroma of natural cocoa.

2. A method according to claim 1, wherein the yeast is dried to a moisture content of less than about 5%, preferably less than 1%, be weight prior to roasting the yeast.

3. A method according to either of claims 1 and 2 comprising the steps of washing the yeast prior to roasting the yeast, preferably hy mixing the food yeast into an aqueous solution containing a yeast washing agent and having a pH greater than about 6.0 to form an aqueous yeast slurry; separating the yeast from the yeast slurry; eluting the yeast to remove a substantial portion of any residual washing agent; drying the yeast to a moisture content of less than about 5% by weight; and finally roasting the yeast. t. A method according to claim 3, wherein the slurry is screened to remove therefrom suspended solids having a particle size greater than about 100 mesh Tyler.

4. 5. The method according to claim 3, wherein the yeast washing agent is a soluble compound having a cation in solution consisting of Na+, K+, Ca++ or mixtures thereof, and having an anion in solution consisting of OH , 00^, HCOy or mixtures thereof.

5. 6. A method according to any one of the preceding claims, wherein the roasted, yeast is wholly or partly substituted for cocoa and/or chocolate in a foodst-:ff. , A method of producing an edible yeast product substantially as herein described and as set forth in the foregoing Examples.

6. 8. An edible yeast product when produced by the nethod of any one of claims 1 to 7.