• 14 Mar
    Essential oils

    Essential oils

    Breaking new ground in the analysis of juice with steam distillation

    The International Fruit and Vegetable Association held a series of Technical Webinars including a Quality webinar with Dr Eduard Wiedenbeck as a guest speaker

    Here we review the analysis of citrus fruit juices, particularly determining the quality of citrus essential oils according to their main constituent, D-Limonene.

    As 2021 was the FAO’s International Year of Fruits and Vegetables, it is inevitable to remind ourselves of the important role that citrus fruits play in maintaining our health. Oranges, lemons and grapefruits are rich in phytonutrients, a type of antioxidant that neutralizes free radicals in our body and prevents many health issues.1 Nevertheless, both as consumers and as producers, we should take a closer look at the quality-related compounds that are present in citrus fruits, especially at D-Limonene, which is the main constituent of citrus essential oils. D-Limonene is mainly present in the peel of citrus fruits, such as oranges and lemons, and is used by the plants as a natural insecticide protecting their nutrient-rich fruits from parasites. For us, the smell of D-Limonene is characteristic of a fresh orange scent which is not surprising considering that more than 90 % of the oil content of oranges is comprised of this compound. In our daily life, D-Limonene is used as a dietary supplement and as a fragrance ingredient for cosmetic products. Because of its refreshing scent, it is often used to mask the bitter taste of alkaloids and for all kinds of cosmetic products. And since D-Limonene is the main constituent of citrus essential oils which are found in the fruit peel, the compound is also present in fruit juice where it contributes to the flavour of the fruit. Due to heavily industrialized juice production with cold press extraction of oranges, it is unavoidable that this compound enters fruit juice in significant amounts.

    D-Limonene – beneficial or not?

    Although it appears to be safe and even positively accepted for most human-related uses, there may also be negative implications if D-Limonene is administered in higher concentrations. If this compound is applied to skin, it may cause irritation from contact dermatitis. This topical effect becomes even more significant when this compound is ingested at high concentrations with irritations in the throat as the consequence. Further studies show that the liver was identified as a critical target organ following oral administration of D-Limonene.2 But should we now stop consuming citrus fruits and their juice products?

    The answer is a comforting ‘no’. Thanks to responsible national authorities such as the European Fruit Juice Association (AIJN) and the United States Department of Agriculture (USDA) which have set maximum levels that should not be exceeded, it is ensured that the consumer gets a taste of the highest quality of juice products. Thanks to these standards, D-Limonene is maintained at low enough concentrations to be harmless. How can one measure D-Limonene levels? An established method with steam distillation according to Scott and Veldhuis has proven its reliability since 1966.3 However, determining D-Limonene via manual steam distillation and subsequent titration analysis is usually tedious, slow and labour-intensive. Some quality control laboratories report that they need 20 minutes just to distil one single sample. Recently, efforts have been made to speed up the process by using a distillation unit with an integrated steam generator. As a result, the steam distillation time has decreased drastically from 20 minutes to 1 minute per sample! More details on these time savings can be found in BUCHI’s latest Application Note. In this case the juice industry should be on a viable way to facilitate a high throughput analysis that is still in line with the established method.

    1 Okwu, D.U.; Citrus fruits: A rich source of phytochemicals and their roles in human health, International Journal of Chemical Sciences 2008, 6(2), 451-471

    2 Lee B.M. et al.; Safety Evaluation And Risk Assessment Of d-Limonene, Journal of Toxicology and Environmental Health 2013, 16 (1), 17-38.

    3 Scott, W.C.; Veldhuis, M.K.; Rapid Estimation of Recoverable Oil in Citrus Juices by Bromate Titration, Journal of Association of Official Analytical Chemists 1966, 49 (3), 628–633.

     Dr Eduard Wiedenbeck is Product Manager for Kjeldahl Solutions at Büchi Labortechnik in Switzerland. He has presented this topic at the IFU Technical Webinars 2021. The webinar can be seen on-demand by clicking here.”



    By Caroline Calder Features
  • 14 Mar
    Sugar reduction

    Sugar reduction


    We have the technology – the key to sweetness exists

    Tetra Pak provide some insight into their ground-breaking tech designed to keep our favourite beverages sweet and delicious, but less of the sugar

    There has been an abundance of attention around reduced sugar drinks, not least because of the much-discussed sugar tax. But juice trails its counterparts in this space.

    Tetra Pak, together with Sumol+Compal, has developed technology that can reduce the sugar content in juice to the exact requirements of the brand using a fermentation process. The fermented de-sugared juice is a true ‘clean label’ product with no additional ingredients.

    This innovative solution can reduce sugar in juice while maintaining its taste profile, colour, mouthfeel, and nutritional content. Using fermentation, it is possible to remove the sugar while keeping all the benefits of the juice, plus fermentation is trendy in the added value category. Indeed, almost a third of the USD1.5 billion invested in alternative proteins last year went towards companies using fermentation.

    According to recent research from Mintel, there is a thirst from consumers globally for this type of product. In Spain, 75% of juice consumers cited sugar as a reason for limiting the amount of juices & smoothies they drink. Meanwhile in China, 43% of juice consumers consider sugar content an important factor in choosing juice drinks. In the UK, 42% of juice buyers say that health benefits would encourage them to spend more on juice drinks.

    1. Can you explain, in layman’s terms, the kind of technology being used to reduce the sugar content in these juices?

    We are using fermentation, a natural biological process to remove sugar while retaining all the benefits of the juice. The secret lies in combining a unique yeast strain with the optimal process and design parameters so that all sugar is removed, and re-blended with standard juice to achieve the desired final product.

    1. How is this technology applied to achieve the desired effect?

    Step 1. Fermentation:

    • Complete sugar removal down to 0% is achieved with optimal process and design parameters in combination with a unique yeast strain which gives consistent product quality – no off flavors, nor increasing the natural acidity present in a fruit juice, thus keeping fruit juice flavour and fundamental nutritional value.
      • By products: the yeast that is added in fermentation tanks is removed in the clarifier
      • By products: the alcohol which is created during fermentation is removed in the de-alcoholisation unit

    Step 2. Clarifier:

    • Removes the yeast cells to stop fermentation process
    • Secure product quality (no rupturing of yeast cells, to avoid sensory impact, very low pulp / turbidity reduction)
    • The yeast size, shape and floculation behaviour, make it possible to remove the yeast while only a minor amount of juice pulp is removed, keeping the juice nutritional and maintaining its sensorial profile
    • The process design does not break the yeast cell walls, meaning that there is no release of off flavour (yeasty) compounds into the juice

    Step 3. De-alcoholisation unit

    • Removing alcohol in a gentle way while keeping juice taste and aromas
    • The quantity is completely controlled
    • The product after the de-alcoholisation unit: a valuable ingredient of 0% desugared juice

    Step 4. Product formulation:

    • The final sugar level in the product is controlled by blending the 0% desugared juice with 100% juice in a normal juice line after the fermentation process
    • With this production line solution, we are able to keep the number of ingredients to a minimum, while maintaining good taste, colour, mouthfeel as well as nutritional content
    1. Were there any R&D challenges? How were these overcome?

    Some of the challenges faced when trying to find a refined process to produce de-sugarised juice included:

    • Watering down and adding low-calorie sweeteners meant that there would be a lower juice content and no increased nutritional density
    • Removing sugars using filtration technologies didn’t achieve the desired sensory result – it resulted in changes to the juice matrix and impacted nutritional value
    • Enzymatic conversion of sugars to a by-product had some impact on sensory result and may not be perceived as a natural process
    • Multiple yeast strains had to be tested to find the optimal solution
    1. Can you tell me more about the fermentation process? What method does your company use to achieve your desired result?

    We decided to use fermentation as it is a natural biological process that can remove sugar while maintaining the taste profile, colour, mouthfeel and nutritional content.

    First, the yeast is added to the juice. Once this has been done, the yeast is then removed by a clarifier, before the alcohol is then removed in a de-alcoholisation unit. This produces the de-sugarised juice and there is then the possibility to re-blend this 0% sugar juice with 100% juice to achieve the desired product, such as 50% sugar juice.

    The specific yeast strain used was selected after screening dozens of strains, and is used in various traditionally fermented foods such as wine or cider.

    1. Can you tell me anything about the patents on this technology? Once the word gets out, how do you foresee other companies making use of this kind of technology? Or is that not possible?

    This technology solution is similar to our revolutionised JNSD line that Tetra Pak launched last year, which was a new combination of existing technology (UV + filter). As such, the de-sugarised juice method is a combination of existing technologies, albeit in a new and unique way.

    Due to the fact that these technologies are already in use, it is not possible to patent. However, in order to achieve the desired quality and benefit from the expert knowledge developed during trials, customers need to combine equipment from Tetra Pak with the unique yeast strain from Sumol + Compal.


    By Caroline Calder Features
  • 13 Jan
    Packaging – Welcome to the solution to cost and carbon reduction

    Packaging – Welcome to the solution to cost and carbon reduction


    Return Logistics – don’t waste valuable materials and don’t waste cost, say Octobox

    With our world changing rapidly, we are having to evolve constantly. Pivoting from our original goals to meet the demands or expectations of our supply chain or the end consumers. This is what makes the Juice Industry so exciting. Things change in commodities – potentially on a daily basis and today this also accounts for how efficient we manage our supply chain.

    Historically the juice industry was born into steel drums, a very robust packaging which was required to ship the cargo in open hatch reefer vessels. With the introduction of reefer containers this type of packaging was no longer required, but nevertheless not changed by most industries, as the steel drum had evolved to an industrial standard. The supply chain had adapted to this type of packaging from filling, to handling, to tipping as well as recipes for blending were based on 200L units.

    Things change; It is no longer necessary to accept the cost of steel drums, which have doubled or tripled in price depending on your location, it is not economic to accept the high tara weight or their very high carbon footprint. All of this for a one-way packaging? These facts can be difficult to explain to consumers, hence why more and more Juice Industries are changing to returnable packaging with the aim to reduce both their cost and their carbon footprint.

    So, how does this work?

    Simple, the packaging has to fold that well, that when its empty you can carry say 400 empty units in one 40” container, but when full only 20 units are used to ship to your destination. The ratio is 20 to 1 in this example. This reduces the cost of returning each unit to five-to-ten dollars per trip. Can you buy this new packaging material at the same cost of the return? The answer is ‘no’, this is how you save cost.

    You have saved the cost of buying new packaging and continue to do so with every trip you make. You also saved carbon emission – at NO cost, to the contrary you can now certify your carbon reduction and sell it or even advertise it to your customer as a benefit.

    No matter what you produce be it concentrate, NFC, puree or pulps, determine which market you have not been able to reach, because your logistic cost including the packaging are too high and Change the cost.

    We were asked to write about return logistics options for the juice industry and of course we would like to promote our own product the Octobox, but more important is that you keep your industry cost to a minimum and help us all to reduce carbon emission – especially where the alternative is so easily available.

    There are quite a few solutions for returnable packing material on the market, please take your time and find the solution best suitable for you. If we at Walton Industrial Containers can be of help or assistance, please contact us and we will help you find a solution for your specific product and destination.

    Or visit us at www.octobox.co.uk – we want to hear from you.

    Walton Industrial Container/Octobox


    By Caroline Calder Features
  • 13 Jan
    Lemon Juice – Quality aspects of Argentinian lemon juice

    Lemon Juice – Quality aspects of Argentinian lemon juice


    Lemon fruit is a rich source of nutrients, including flavonoids, citric acid, vitamin C and minerals (e.g. potassium), which provide numerous health promoting properties. Dr Soraya Bellini, Head of Food Chemistry at CIATI in Argentina, discusses.


    Lemon production is limited to a small number of countries and regions because of the plant’s extreme sensitivity to low temperatures. Argentina is one of the southernmost countries around the world, with tropical weather in the North and produces around 3,542,000 tonnes of fresh citrus fruits annually. Of the 364,800 tonnes exported in 2020, 68% corresponds to lemon, 22.5% to orange, 9.2% to mandarin and 0.2% to grapefruit. Argentina is the second exporter of lemons and it is the first exporter of concentrated lemon juice and essential oils.

    Argentinian lemon industries are integrated companies so they have control throughout the entire production chain. 70% of fruit production goes to by-product production, such as concentrated juice, essential oils and dry peel or pectins. Nowadays, the industries are producing Not From Concentrate Juice (NFC), obtained by simple fruit squeezing and a mild pasteurization.

    All these products are obtained from first quality fruit and they are commercialized in internal and external markets.  Most companies work under a GSFI (Global Food Safety Initiative) or another quality system and most of them work with SGF (Sure Global Fair), which is a voluntary control system.

    The levels of different compounds vary in juices prepared from different lemon cultivars, maturity stage, growing region, cultural practice, storage conditions of fruits, extraction procedure and thermal treatment of juice. The Argentinian lemon juice has distinctive chemicals characteristics with respect to lemon juice in the rest of the world such as: colour, flavour, pulp ratio and soluble solids/acidity ratio, presenting advantages in the international market.

    Quality controlled

    Regarding the parameters that characterizes the absolute quality requirements such as environmental, hygienic and industrial requirements are all inside the range of values established in the reference guideline (AIJN, 2019) and lemon juice from Argentina presents high concentration of vitamin C, which is another valuable quality characteristic in this product.


    Concentrated lemon juice from Argentina does not contain heavy metal elements such as arsenic (As), lead (Pb), cadmium (Cd), Tin (Sn) and mercury (Hg).  The industry is evaluating these pollutants including nickel (Ni). The results in more than 1700 analysis, are below the limit of quantification in As, Cd, Sn and Hg (Table 1). Only 1% of samples have resulted positive in Pb, but the values are within the AIJN range.

    Table 1: Limits of quantification of heavy metals on concentrated lemon juice.

    Heavy metals LoQ (Limit of Quantification)
    Arsenic 10 µg/kg
    Cadmium 6 µg/kg
    Lead 10 µg/kg
    Mercury 10 µg/kg
    Tin 1 mg/kg

    5-hydroxymethylfurfural (5-HMF) is not present in direct fruit juice, but it is naturally generated during heating or storage processes in the Maillard reaction as well as sugar caramelization and degradation. Therefore, 5-HMF can be used as an indicator of thermal abuse and prolonged or improper storage. In all lemon juice samples tested, concentration of 5-HMF was much lower than 1 mg/l. The maximum value allowed is 20 mg/l (AIJN, 2019).

    With respect to the evaluation of identity and authenticity, when comparing the results of Argentinian lemon juice with AIJN parameters, we can see other characteristics that differentiate it from other countries juices.


    The organic acid composition is one of these parameters, for example:

    • L-malic acid values are usually in the upper part of the AIJN range and 60% of results are above 4 g/l.
    • D-Isocitric acid has different values with respect to lemons of tropical weather. The Argentine results are near the minimum of AIJN´s range (average value 285 mg/l), while South Africa has a maximum value of 350 mg/l. These low values make the ratio citric acid/d-isocitric acid high. Although the average of ratio citric/isocitric acid is within AIJN´s value, more than 20 % of samples are above maximum AIJN value. Argentine authentic juice can present values up to 240.

    On the other hand, sugar composition is another parameter that is different. The average values are shows in the Table 2. Although all sugars are within AIJN´s ranges, the average in Argentine juice is below the international average. The level of sucrose is lower when it is compared with Mediterranean juice.  This is due to the weather conditions in the area, having wide temperature ranges.

    Table 2: Sugar content in Argentine lemon juice at 8 °Bx.

    Sugars Level in juice
    Sucrose (g/l) 2.1 ± 0.8
    Glucose (g/l) 5.5 ±1.2
    Fructose (g/l) 5.1 ± 1.1
    Glu/fru 0.94 – 1.3
    Sugar free extract (g/l) 65 -78


    Formol Number (also known as formol index) is another parameter of the Argentine fruit juice which is lower than AIJN ranges for the different kinds of juice, and the lemon is not the exception where the average value in Argentina juice is in the minimum of the AIJN range (AIJN, 2019). Although the Formol Number value is low, the amino acids values are within the range. The Table 3 shows the comparison, and some of them are below the range average. We can also observe that Lysine is the amino acid which presents more variability between seasons.

    Table 3: Aminoacids content in Argentine lemon juice at 8 °Bx.

    Aspartic acid 477 300 – 800
    Glutamic acid 192 160 – 400
    Threonine 14 10 – 30
    Asparagine 406 130 – 600
    Glycine 10    7 – 25
    Valine 14     8 – 35
    Proline 267  100 – 800
    Isoleucine 9.7 3 – 10
    Leucine 5.4  3 – 10
    Lysine 5.3  5 – 10
    Phenilalanine 14.7  8 – 40



    This article summarizes the different characteristics present in genuine lemon juice from Argentina, as a conclusion, lemon juice from Argentina is within the ranges established by AIJN for certain parameters, however some of them are in one extreme of the range. It also presents some distinctive characteristics that differentiates it from other countries juices. Argentina lemon juice industries work on their self-quality control to guarantee the commercialization of its products, being Argentina one of the leading countries in the production of concentrated lemon juice.



    AIJN (Association of the Industry of Juices and Nectars of the European Union) (2019). Code of practice for evaluation of fruit and vegetable juices 6.6. Reference guideline for lemon juice – Revised September 2019.

    Dr Soraya Bellini is Head of Food Chemistry at CIATI in Argentina. She has presented this topic at the IFU Technical Webinars 2021. The webinar can be seen on-demand by clicking here.”


    By Caroline Calder Features
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