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Fermentation
Fermentation is a mechanism which requires the use of microorganisms such as bacteria and yeast in order to break down carbohydrates into other by-products such as alcohol and organic acids. Also proteins and lipids can be broken down through fermentation.

Fermentation is typically accomplished in environments in which oxygen is absent (anaerobic). The 2 methods of fermentation are lactic acid fermentation and alcoholic fermentation which have been used for centuries. Through fermentation, products such as wine, cheese, yogurt, pickles and  preserved lemons are produced. Several health benefits are associated with fermented foods such as an increase in the production of B-vitamins. Through fermentation B-vitamins, omega-3 fatty acids, and probiotics are made. B-vitamins have shown to be good for the gut. Additionally, food that is normally indigestible can be digested once the food has been fermented due to bacterial synthesis which allows the digestive tract to absorb more nutrients from the food (increased bioavailability).

Nutritional Value
In contrast to the unpeeled lemon, the amount of vitamins within the preserved lemons is reduced, along with a loss of minerals and simple carbohydrates such as sugar and starch. It can be concluded that due to the preservation procedure of fermentation, the nutritional value of the preserved lemons is reduced.

Physical and Chemical Changes
The process of fermentation is a complex one and causes a multitude of changes at the exterior and interior levels of the lemon. All of the known exterior changes are observable with the human eye. These changes include a wrinkling of the skin along with a slight browning of the interior portion of the lemon (if sliced), due to oxidation.

Although there is not much research on the chemical reactions that take place within lemons during the preservation process of fermentation, using research based on other fruits and through observation, conclusions can be made with supporting evidence. With the definition above we can be concluded that the sugar and starch within the lemons are chemically broken down during the fermentation process. Based on the nutritional value, it can also be theorized that protein is broken down or hydrolyzed during the fermentation process as there is an absence of the macronutrient post-fermentation.

There are also a number of factors that can influence the success rate and level of safety in regards to fermentation. Fermentation can be heavily affected by compositional factors within the fruit such as pH, buffer capacity and initial sugar content. All of these factors can be altered depending on the size of the fruit as the larger the fruit, the more nutritional value the fruit will hold. Additionally, pesticides can have a huge effect on fermentation. If pesticides are left, in large quantities, on the fruits surface during fermentation, the process of preservation increases the potency of the hazardous materials within the pesticides.

Role of Minerals, Acids and Antioxidants in Fermentation
A common micronutrient used in curing is salt, which absorbs moisture and binds to water. This effect makes it a difficult environment for the bacteria to survive in and helps extend shelf life. Some recipes also suggest the use of lemon juice, which is a citric acid that helps lower the pH, allow acid-producing organism to growth and prevent the growth of spoilage and disease causing microorganism. For preservation of lemons, the use of antioxidants as a food additive is used to prevent lipid peroxidation and the fading of food color.

Lemons fermentation involves citric acid fermentation which is the most important organic acid produced in tonnage and is extensively used in food and pharmaceutical industries. It is produced mainly by submerged fermentation using Aspergillus niger or Candida sp. from different sources of carbohydrates, such as molasses and starch based media. The food and beverage industries use this acid extensively as a food additive globally.

In addition, zinc plays a role in the regulation of growth and citric acid accumulation. High zinc maintains citric acid's growth phase (when the cells proliferate but do not accumulate citrate), while at low zinc the cultures pass into accumulating phase (when they produce citrate but do not proliferate). Addition of zinc to accumulating cultures results in their reversion to growth phase. Iron, manganese, calcium at high concentrations had no influence on either growth or citrate accumulation.