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Lemon Juice

Extraction

Citrus fruit juices are most commonly extracted by FMC extractors, which are commercially used citrus juice extractor machines[1]. When a lemon is fed into an FMC extractor, it is placed on a half-sphere cup made of prongs. To juice the fruit, another cup descends faced-down on to the lower cup, such that the prongs of the upper and lower cups criss-cross with each other as the fruit is squeezed. Simultaneously, a cylindrical knife placed below the lower cup drills into the fruit and acts as a tube for the juices to flow through and collect. Next, the extracted juice is clarified of pulp by being spun in a centrifuge.

To create a juice concentrate, the extracted and clarified juice is passed through an evaporator, which uses heat to evaporate the water from the juice, thereby “concentrating” the extract[2]. Afterwards, the juice concentrate may be pasteurized, but most packaged forms of the concentrate does not require pasteurization as the heat from the evaporation step will have sufficed to control any unwanted microbial activity[2].

Preservation

The preservation of lemon juice concentrate is primarily affected by temperature. The only known way to prolong flavour, colour stability, and nutritional value is storage at low temperatures through refrigeration. However, these attributes can deteriorate rapidly if storage temperatures rise. Storage at ambient temperatures (12.22℃-31.77℃) results in an expedited degradation of acidity, total sugars, ascorbic acid, amino acids and phenols[3]. Lemon juice concentrate is particularly susceptible to ascorbic acid degradation in temperatures exceeding 28℃[4]. All of these factors impact the nutritional value and product appeal of lemon juice concentrate. There is still a consistent degradation at refrigeration temperatures but this occurs much less quickly. These effects are possibly further slowed by the use of cation exchange resin treatment to remove amino acids[3]. Amino acids in concentrate cause browning, colour deterioration, and a general reduction in aesthetic quality[3]. They are also not a major reason for consumption of lemon juice concentrate which would make their removal not a significant concern for consumers. However, the only reliable way to preserve unsealed lemon juice concentrate remains storage at refrigeration temperatures.

Packaging

According to the Canadian Food Inspection Agency, lemon juice must be dispensed in containers that meet the following characteristics[5]:

• Non-porous

• Non-corrosive

• Made of food-grade materials

• Cleaned and inverted prior to use

CFIA regulations do not specify materials for containers, but plastic and glass bottles are the most common in the industry. In the case of plastic bottles or lemon-shaped containers, manufacturers must use new caps[5]. In the case of glass bottles, manufacturers are allowed to reuse containers as long as they are properly cleaned, sanitized and rinsed[5].

After packaging, unpasteurized lemon juice must be refrigerated (0 to 4 oC) or frozen (less than 18 oC). These temperatures must be held constant until they are ready for consumption[5].

Lemon juice labels must meet the standard requirements established by the Food and Drugs Act and Regulations and the Consumer Packaging and Labelling Act. If the juice is unpasteurized it should be indicated in the label. Preservatives (additives) must be declared. A “best before date” must be indicted on the container.[5]

Distribution

Lemon Juice, once processed and packaged, is distributed mainly through supermarkets, hypermarkets, and food services to the general public[6]. As it is highly perishable, maintaining freshness requires cold bottling temperatures, a sanitary environment, and state of the art equipment[7]. We can find concentrated lemon juice in non-refrigerated areas of markets because concentrated lemon juice is easier to store and distribute in comparison to fresh lemon juice. The Canada Food Inspection Agency also requires that all potential sources of fecal contamination of bins and fruit must be minimized during handling and transport. Bulk unpasteurized juice and cider must be transported at refrigeration temperatures between 0-4ºC to the packer[8].

Uses and Nutritional Value

Lemon juice are commonly known for their high nutritional value. Often mixed with fresh water as a nutritious drink, lemon juice is rich in Vitamin C, beta carotene, folate, calcium, magnesium, phosphorus and potassium[9]. Consequently, lemon juice aids digestion, constipation relief, immunity, or fat metabolism among many other benefits[10]. Therefore, careful processing methods should be employed to minimize nutrient loss.

Lemon juice may be used in cooking for the addition of desired flavour or for preservation purposes. As a acidic food (pH < 4.6) full of ascorbic acid (Vitamin C), it will prevent oxidative browning of certain foods such as apples[11]. Alternatively, lemon juice can be employed as a natural cleaning agent thanks to its high acidity, which will create an undesirable environment for microbial growth and function[12].

juice
Nutritional value per 100 g (3.5 oz)
Energy2 kJ (0.48 kcal)
2
2
2
Vitamins and minerals
MineralsQuantity
%DV
Calcium
8%
100 mg
Percentages estimated using US recommendations for adults,[13] except for potassium, which is estimated based on expert recommendation from the National Academies.[14]
  1. ^ "Citrus Juices Processing Technology". Citrech Snc. Retrieved Aug 9, 2018. {{cite web}}: Cite has empty unknown parameter: |dead-url= (help)
  2. ^ a b "Product Types - Fruit Juice Concentrates". www.cobell.co.uk. Retrieved 2018-08-09.
  3. ^ a b c Sharma, S K (May 2004). "Effect of temperature and removal of amino acids on non-enzymatic browning of lemon juice concentrates during storage" (PDF). Journal of Scientific and Industrial Research. 63: 444–451.
  4. ^ Burdurku, Hande Selen (May 2006). "Degradation of vitamin C in citrus juice concentrates during storage". Journal of Food Engineering. 72: 211–216.
  5. ^ a b c d e Safety, Government of Canada,Canadian Food Inspection Agency,Agrifood, Meat and Seafood. "Code of Practice for the Production and Distribution of Unpasteurized Apple and Other Fruit Juice/Cider in Canada". www.inspection.gc.ca. Retrieved 2018-08-09.{{cite web}}: CS1 maint: multiple names: authors list (link)
  6. ^ Canada, Agriculture and Agri-Food Canada;Government of. "Fruit Juices In China". www.agr.gc.ca. Retrieved 2018-08-09.{{cite web}}: CS1 maint: multiple names: authors list (link)
  7. ^ "Natural Brands - Home Page". naturalbrands.com. Retrieved 2018-08-09.
  8. ^ Safety, Government of Canada,Canadian Food Inspection Agency,Agrifood, Meat and Seafood. "Code of Practice for the Production and Distribution of Unpasteurized Apple and Other Fruit Juice/Cider in Canada". www.inspection.gc.ca. Retrieved 2018-08-09.{{cite web}}: CS1 maint: multiple names: authors list (link)
  9. ^ McCarron, Joshua. "Benefits of Fresh Lemon Juice With Rind". LIVESTRONG.COM. Retrieved 2018-08-09.
  10. ^ "UBC Library | EZproxy Login". search.proquest.com. Retrieved 2018-08-09.
  11. ^ "Keep Apples Fresh | Stop Apples From Browning Using Lemon Juice". Home Science Tools. 2017-10-18. Retrieved 2018-08-09.
  12. ^ Palmer, Pamela (2009-04-08). "Natural Cleaning Product Reviews | Green Keen: Lemon "The" Natural Cleaner and Disinfectant | Natural Cleaning Product Review". Natural Cleaning Product Reviews | Green Keen. Retrieved 2018-08-09.
  13. ^ United States Food and Drug Administration (2024). "Daily Value on the Nutrition and Supplement Facts Labels". FDA. Archived from the original on 2024-03-27. Retrieved 2024-03-28.
  14. ^ National Academies of Sciences, Engineering, and Medicine; Health and Medicine Division; Food and Nutrition Board; Committee to Review the Dietary Reference Intakes for Sodium and Potassium (2019). Oria, Maria; Harrison, Meghan; Stallings, Virginia A. (eds.). Dietary Reference Intakes for Sodium and Potassium. The National Academies Collection: Reports funded by National Institutes of Health. Washington, DC: National Academies Press (US). ISBN 978-0-309-48834-1. PMID 30844154. Archived from the original on 2024-05-09. Retrieved 2024-06-21.