Conquering Shelf-life Issues of Chocolate Ingredients, processes, packaging and ambient conditions all affect shelf life. Understanding and controlling these factors will help to ensure product quality and encourage repeat purchases. Marlene Stauffer Blommer Chocolate Co. All foods are perishable by nature. minerals and vitamins. It is an intimate mix- Numerous changes can take place in foods ture of solid particles suspended in fat. during processing and storage. Conquer- Chocolate is very shelf stable due princi- ing shelf-life issues in confections can be pally to the unique properties of cocoa. challenging, to say the least. This paper Chocolate contains cocoa butter and, some- will define shelf life and discuss issues times, milk or milk fat. It has a fast flavor directly impacting shelf life, such as for- release and melts at body temperature. mulation, manufacturing, storage and dis- Cocoa solids contain a natural antioxidant Marlene Stauffer is tribution, and then discuss possible reme- in the form of tocopherols, and cocoa but- the director of quality assurance/research dies to overcome these issues. ter breaks down to inoffensive short-chain and development at fatty acids.As a result, most chocolate prod- Blommer Chocolate WHAT IS SHELF LIFE? ucts can be classified as medium- or long- Company. She has life products. Compound coatings contain been with Blommer The shelf life of a food product is the period vegetable fat, have a slower flavor release since 1982. of time during which it will retain accept- and can be heat resistant. When adding able appearance, aroma, flavor and texture. inclusions and making candies using choco- Key elements of shelf life for the confec- late, shelf-life factors can be altered and tioner are microbiological safety, eutetics, categorized into two main classes: bloom, migration (fat or moisture), loss of • Those which are inherent in the product texture and rancidity. itself and cannot be prevented by pack- Chocolate is a high-energy foodstuff with aging alone. a complex nutritional profile, containing • Those which are dependent on the envi- fat (either cocoa butter or, if it is a confec- ronment and may be controlled. tionery coating, vegetable fat), carbohy- In a perfect world, making mouthwatering drates and protein. It does provide some confections today and selling them tomor- ➤ The Manufacturing Confectioner • February 2007 47 Conquering Shelf-life Issues of Chocolate The formulation row is ideal, but many factors influence syrup solids than sucrose solids in chosen for a how these candies get to our consumers, caramel. such as raw material availability, season- confection can Moisture ality, distribution and consumer demand. directly impact how • Moisture migration can occur when a well the flavor and Microbiological safety is critical in con- drier inclusion comes in contact with a texture are fectionery products. Raw nuts may con- higher-moisture piece, causing the tex- maintained. tain pathogens; products must therefore ture to become more hard. be processed and stored to prevent this. • Keeping a meltaway smooth upon stor- Milk may contain listeria, making it crit- age may require actual tempering of ical to avoid moisture and condensation. the chocolate with the added fat before going further in the process. A raw-material and finished-product test- ing program needs to be in place to mon- Fat Migration itor your environment and products • Everything likes to come to equilib- going out the door. A hold/release pro- rium — a balanced state or unchanging gram will prevent any products from get- system. ting out of your control. • Center fats will rise to the surface, soft- ening chocolate and hardening the cen- ter. FORMULATIONS • Consult your specialty fat supplier to The formulation chosen for a confection formulate the correct fat for your can directly impact how well the flavor recipe. and texture are maintained. Let’s look • Milk fat is often added to dark choco- at a few examples to see what impacts late to provide protection against shelf life. bloom, delaying the transformation from form V to form VI (the highest Eutetics/Softening of a Coating melting polymorphic form). • Eutetics could occur, decreasing shelf life and causing the product to bloom, Oxidative Rancidity with the possibility of fat deterioration • Oxidative rancidity can occur relatively when incompatible fats are blended rapidly when high-fat centers or roasted together in a formula. nuts are used in a formulation. • Cocoa butter and palm kernel oil are • Centers may not be completely coated not compatible and will cause soften- when using nuts, exposing the choco- ing and eutetics when mixed together, late and nuts to the possibility of bloom. even in small quantities. • Stale or cardboardy flavor can also • A general rule of thumb is to not mix occur. more than 4 percent of the fat with cocoa butter when manufacturing a compound coating. MANUFACTURING Whether confections are manufactured by Graining hand or using factory equipment, condi- • In a caramel, graining can occur if all tions must be maintained to maximize shelf the sugars are not dissolved before com- life. For moulded pieces, one must use prop- pletion of the cooking cycle. At least 25 percent moisture in the caramel pre- erly tempered chocolate in room-temper- mix and heating to 160° to 180°F while ature moulds that pass through a cooling agitating can aid in this process. tunnel to set the product for shrinkage and • A rule of thumb is to have more corn easy demoulding. Good mould design and ➤ 48 February 2007 • The Manufacturing Confectioner Conquering Shelf-life Issues of Chocolate consistent moulding procedures will min- • If a piece has an uneven surface to coat, Confections do not imize potential problems. this could cause the center to be like temperature exposed, creating conditions for During enrobing a center is passed variation and reduced shelf life. through a curtain of chocolate or com- prefer constant • Incorrect viscosity may also alter cov- pound coating and then over a bottomer erage rate as well as increase feet temperature and to coat the bases. Sometimes bases are formed at the base of each piece. humidity during coated with a compound coating first to storage. aid in integrity or to prevent fat migra- Cooling tion, and then enrobed with chocolate. • Chocolate and compound require dif- Pieces can also be double enrobed to ferent cooling tunnel conditions. ensure extra coating if the center is vul- –Chocolate needs to be cooled gently with moderate air flow (55° to 60°F). nerable to softening or leakage, or difficult –Compound coatings are best cooled to coat. If enrobed centers are cooled too in colder tunnels (40° to 45°F) because rapidly, the chocolate could crack; if they spontaneously solidify in a stable cooled too slowly, it could end up discol- crystal form. ored and soft. The big issue is that this • All tunnels should warm to nearly room problem may not be apparent right away temperature at exiting to prevent con- and could emerge later in the distribution densation. process or when your customer purchases the product. PACKAGING AND STORAGE ISSUES Packaging types will have a great influ- Solid Chocolate ence on the stability of the confectionery Temper product over time.The goal is to keep fla- • Improperly tempered chocolate will vor and texture in and moisture or off-fla- continue to stabilize after the product is vors out. Moisture can cause cracking of, wrapped and has left the factory, which may lead to soft texture and the appear- for example, pretzels coated with choco- ance of fat crystals or bloom. late and could make them soggy. Milk • Lack of contraction (shrinkage) in a chocolate is more susceptible to flavor mould for product releases can be due degradation if packaging is not controlled. to improper tempering. There are many types of packaging mate- • Dull appearances, poor snap and long rials such as polypropylene, metalized or set times can be from improper tem- multilayered films. Packaging suppliers pering. are excellent resources for the best type of Moulding packaging for a specific product. • Improperly designed moulds can lead Following are some things to take into to poor-quality products. consideration: • Warm moulds can delay onset of crys- • Heat sealing — be careful if shrink film- tallization. ing is used; this could cause bloom due to excessive heat. • Cold moulds can expose chocolate to premature cooling, forming incorrect • High-moisture pieces may lose and trap crystals. moisture. This could cause molding if tight packaging is being used. Some- Enrobing times wax paper is the best option due • If centers are too warm, they can detem- to its semi-permeability. per the chocolate. • Packaging material could cause off- ➤ The Manufacturing Confectioner • February 2007 49 Conquering Shelf-life Issues of Chocolate White chocolate is odors and off-flavors from inks used, preserve freshness and halt center oil especially the type of material in the packaging migration. Care must be taken with and from where the packaging has been susceptible to light- delicate shells so they do not crack stored. during the rewarming process. This induced • The Robinson test can be used to eval- must be carefully controlled to pre- degradation of uate if packaging materials are a source vent condensation from forming on flavor due to its of off-flavors. Place a folded piece of the products. lack of natural the packaging material (20 cm × 22 cm) • Compound coatings would be more antioxidants. along with 15 grams of grated choco- heat resistant than chocolates mainly late in a sealed jar. Place the jar in the Exposed nut pieces due to higher melting points with some dark at room temperature (20°C/68°F) would also be compound coatings and the fact that at 75 percent rh (if needed, add satu- they do not require tempering.