Chlorophyll

Chlorophyll is a natural green pigment found in almost all plants and algae, playing a critical role in photosynthesis, the process by which plants convert light energy into chemical energy. It is responsible for the characteristic green color of leaves and various green vegetables. Chemically, chlorophyll is a porphyrin ring compound, similar in structure to heme in blood, but with a magnesium ion at its center instead of iron.

There are several types of chlorophyll, primarily chlorophyll a and chlorophyll b, differing slightly in their molecular structure. While chlorophyll itself is abundant in nature and consumed daily in green foods, it is relatively unstable when isolated. It is susceptible to degradation by light, heat, and acidic conditions, which can lead to a loss of its green color and changes in its chemical structure.

The CAS (Chemical Abstracts Service) number 1406-65-1 provided for 'Chlorophyll' specifically refers to 'Chlorophylls and Chlorophyllins, copper complexes.' This is a crucial distinction. Copper chlorophyllins are derivatives of natural chlorophyll where the central magnesium atom has been replaced by copper, and the phytyl tail (a long hydrocarbon chain) is often removed, making them more stable and water-soluble than natural chlorophyll. These copper complexes are widely recognized and used as food colorants.

Naturally, chlorophyll is a fundamental component of all green plant-based foods, from spinach and kale to broccoli and peas. In the context of food additives, the direct addition of isolated, natural chlorophyll as a functional ingredient is not widespread due to its inherent instability. As such, the specific additive function for 'Chlorophyll' in its raw, isolated form is often categorized as unknown in regulatory contexts, as it doesn't typically serve a defined technical purpose when added directly as an isolated, unmodified additive.

However, the derivatives associated with CAS 1406-65-1, namely copper chlorophyllins (often denoted as E141 in Europe and approved by the FDA as Copper Chlorophyllin), are extensively used in the food industry. Their primary function is as a green food coloring. They impart a stable green color to a variety of products, including confectionery, dairy products, beverages, sauces, and soups. Unlike natural chlorophyll, these copper complexes are stable under typical food processing conditions, retaining their vibrant green hue over time and across different pH levels. This stability is why they are preferred over natural chlorophyll for coloring applications.

The safety of consuming natural chlorophyll as part of a regular diet of green vegetables is well-established, given its omnipresence in healthy foods. For 'Chlorophyll' as a direct additive (without specific processing or modification), the information provided indicates 0 adverse events reported to the FDA and 0 recalls, which aligns with its limited direct use as an isolated additive.

For its derivatives, the copper chlorophyllins (E141), comprehensive safety assessments have been conducted by regulatory bodies worldwide. The European Food Safety Authority (EFSA), for example, has evaluated the safety of chlorophylls (E140) and chlorophyllins (E141) as food additives. In its re-evaluation, EFSA concluded that chlorophylls and chlorophyllins, copper complexes (E 140(i), E 140(ii), E 141(i) and E 141(ii)) are not genotoxic and are of no concern with regard to carcinogenicity. An Acceptable Daily Intake (ADI) of 15 mg/kg body weight per day was established for the sum of chlorophylls, chlorophyllins, and their copper complexes, expressed as copper chlorophyll. The copper in these complexes is tightly bound, meaning its bioavailability is very low, and it does not contribute significantly to the total dietary copper intake from other sources, thus posing no risk of copper overload at typical consumption levels.

In the United States, 'Chlorophyll' itself is not listed as generally recognized as safe (GRAS) by the FDA, nor is it explicitly approved as a food additive with a defined function under Title 21 of the Code of Federal Regulations. This aligns with the understanding that natural chlorophyll, due to its instability, is not typically used directly as an isolated food additive.

However, the derivatives, specifically 'Copper Chlorophyllin' (which falls under the CAS 1406-65-1 family), are approved by the FDA as a color additive exempt from certification for use in specific foods. For instance, 21 CFR 73.135 details its permissible use as a colorant in gelatin desserts, puddings, dairy products, and other foods, under specified conditions and maximum usage levels. This regulatory status distinguishes the processed, stable derivative from the raw, unstable natural pigment.

In the European Union, chlorophylls (E140) and chlorophyllins, copper complexes (E141), are authorized as food colorants under Regulation (EC) No 1333/2008 on food additives. Both E140 and E141 are permitted for use in a wide range of food categories at quantum satis (as much as necessary to achieve the desired effect, without exceeding ADI) or at specified maximum levels, following their positive safety re-evaluation by EFSA.

Key studies concerning 'Chlorophyll' as a food additive predominantly focus on the safety and efficacy of its stable derivatives, the copper chlorophyllins. EFSA's comprehensive scientific opinion on the re-evaluation of chlorophylls (E 140) and chlorophyllins, copper complexes (E 141) as food additives, published in 2015, stands as a cornerstone for their regulatory approval in the EU. This opinion reviewed extensive toxicological data, including studies on absorption, distribution, metabolism, excretion, subchronic and chronic toxicity, genotoxicity, carcinogenicity, and reproductive and developmental toxicity. The ADI of 15 mg/kg body weight per day was derived from a no-observed-adverse-effect level (NOAEL) in a chronic toxicity study, applying appropriate safety factors.

Further research has investigated the stability of copper chlorophyllins under various food processing conditions, confirming their robustness compared to natural chlorophyll. Studies have also examined the bioavailability of copper from these complexes, consistently finding that the copper is tightly bound within the molecule, leading to minimal absorption and thus not posing a significant dietary copper burden. These studies collectively support the safe use of copper chlorophyllins as color additives at established regulatory limits.