Loss Of Carotenoids Research Articles

Reducing carotenoid loss during storage by co-encapsulation of pequi and buriti oils in oil-in-water emulsions followed by freeze-drying: Use of heated and unheated whey protein isolates as emulsifiers.

Buriti and pequi oils are rich in carotenoids and beneficial to human health; however, carotenoid oxidation during storage causes color loss in foods, making it difficult to use these oils in food products. This research aimed to encapsulate pequi oil and co-encapsulate pequi and buriti oils by emulsification using whey protein isolate (WPI) as an emulsifier in two forms, natural (unheated) and heated, followed by freeze-drying. The emulsions were studied by droplet size under different stress conditions, instability index, and rheology. The freeze-dried (FD) samples were studied after accelerated oxidation and the total carotenoid retention was determined; for the reconstituted FD, the zeta potential and droplet size were recorded after storage at 37°C for 30days. The emulsions were stable in all conditions, with average droplet sizes between 0.88±0.03 and 2.33±0.02μm, and formulations with heated WPI presented the lowest instability index values. The FD's zeta potential values ranged from -50±3 to -32±3mV. The co-encapsulated oils presented higher carotenoid retention (50±1 and 48±1%) than the free oils (31±2%) after 30days. The oxidative stability indexes were 51±4 and 46±3 for the co-encapsulated oils with unheated and heated WPI, respectively, and 20.5±0.1h for the free oils. FD formulations with 1:3 ratio of oil: aqueous phase and heated or unheated WPI showed the best carotenoid retention and oxidative stability, indicating that FD oil emulsions have potential as next-generation bioactive compound carriers.

Traditional green leafy vegetables as underutilised sources of micronutrients in a rural farming community in south-west Nigeria I: estimation of vitamin C, carotenoids and mineral contents

Objective: To determine the micronutrient composition of fresh and boiled traditional green leafy vegetables (TGLVs). Design: Sixteen TGLVs categorised into cultivated and uncultivated vegetables were analysed for vitamin C (ascorbic acid [AA] and dehydroascorbate [DHAA]), β-carotene, lutein and minerals. Results: Basella alba had the highest AA (72 mg/100 g) content; Vernonia amygdalina (unwashed), had the highest β-carotene and lutein concentrations (14.1 and 29.0 mg/100 g, respectively); Amaranthus hybridus had the highest AA (43 mg/100 g) and β-carotene (9.3 mg/100 g) content, for cultivated sp. Celosia argentea had the highest Fe content; Zn content of all the vegetables was low, 0.4–2.6 mg/100 g. Cooking resulted in significant losses in AA content in all the samples, 19% in B. alba to 100% in Crassocephalum crepidioides. Carotenoid losses were observed in 10 samples and six samples had increased values of β-carotene (12% to 183%) and lutein (64% to double). Conclusion: Traditional green leafy vegetables studied were found to be rich in the micronutrients of interest, especially in carotenoids. Boiling of leafy vegetables, as traditionally done, led to considerable losses of the micronutrients. The micronutrient content of uncultivated leafy vegetables compared well with commonly cultivated species.

Characterization of the behavior of carotenoids from pitanga (Eugenia uniflora) and buriti (Mauritia flexuosa) during microemulsion production and in a dynamic gastrointestinal system.

Uncommon tropical fruits are emerging as raw-material for new food products with health benefits. This work aimed at formulating and processing microemulsions from pitanga (Eugenia uniflora) and buriti (Mauritia flexuosa) fruits, since they are very rich in carotenoids (particularly lycopene and β-carotene), in order to encapsulate and increase carotenoids' bioaccessibility. Pitanga and buriti microemulsions were produced by applying a direct processing (high-speed homogenization at 15,000rpm and ultrasound with 20kHz probe at 40% amplitude) of the whole pulp together with surfactant (Tween 80 or Whey Protein Isolate at 2%) and corn oil (5%). All treatments (HSH-US for 0-4, 4-0, 4-4, 4-8min-min) applied were able to increase the amount of carotenoid released. However, the processing also decreased the total amount of carotenoids in the whole pulp of studied fruits. The impact of processing during microemulsion production was not severe. The overall data suggest that the presence of surfactant and oil during processing may protect the carotenoids in fruits and microemulsions. Final recovery of total carotenoids, after passing the samples through a dynamic gastrointestinal system that simulates the human digestion, was higher for microemulsions than for whole pulps. High losses of total carotenoids in buriti and β-carotene and lycopene in pitanga occurred during jejunum and ileum phases. The present work confirms that it is possible to increase β-carotene and lycopene bioaccessibility from fruits by directly processing microemulsions (p < 0.01).

Mutational loss of carotenoids in alkaliphilic Bacillus pseudofirmus OF4 results in sensitivity to oxidative stress and growth at high pH.

Alkaliphilic Bacillus pseudofirmus OF4, which has a broad pH growth range of 7.5 to above 10.5, is yellow-pigmented due to carotenoids. Carotenoids contribute to membrane rigidity and can alleviate cellular oxidative stress. This study was undertaken to gain insight into the roles carotenoids play in alkaliphile physiology. Carotenoid content was high in stationary phase and in cells grown nonfermentatively at pH 10.5 A colourless mutant was isolated by the in-frame deletion of a key carotenogenic gene, crtM. In cells grown to stationary phase in a pH 10.5 medium with a suboptimal concentration of Na+, the ∆crtM strain exhibited lower resistance to paraquat and hydrogen peroxide. Preincubation of the mutant in a nutrient-free pH 10.5 buffer revealed a pronounced sensitivity to hydrogen peroxide in growth at pH 7.5. In growth curves in media with optimal or suboptimal nutrient concentrations conducted at 37°, the mutant grew identically to the wild-type at pH 7.5 but its lag time was longer than the wild-type at pH 10.5 and growth was slower when the carbon source, malate, was limiting. When the temperature of the growth curves was lowered to 25°, the mutant no longer had a pH 10.5 phenotype, implicating the effect of carotenoids on membrane rigidity for the pH 10.5 growth phenotype. These results suggest that carotenoids in B. pseudofirmus OF4 play a role in managing oxidative stress when cells are adapting to other stressful conditions such as nutrient limitation while also helping to maintain membrane fluidity/rigidity balance for membrane-linked functions.

Stabilization of Crystalline Carotenoids in Carrot Concentrate Powders: Effects of Drying Technology, Carrier Material, and Antioxidants.

Coloring concentrates of carotenoid-rich plant materials are currently used in the food industry to meet the consumer’s demand for natural substitutes for food colorants. The production of shelf-stable powders of such concentrates comes with particular challenges linked to the sensitivity of the active component towards oxidation and the complexity of the composition and microstructure of such concentrates. In this study, different strategies for the stabilization of crystalline carotenoids as part of a natural carrot concentrate matrix during drying and storage were investigated. The evaluated approaches included spray- and freeze drying, the addition of functional additives, and oxygen free storage. Functional additives comprised carrier material (maltodextrin, gum Arabic, and octenyl succinic anhydride (OSA)-modified starch) and antioxidants (mixed tocopherols, sodium ascorbate). Degradation and changes in the physical state of the carotenoid crystals were monitored during processing and storage. Carotenoid losses during processing were low (>5%) irrespective of the used technology and additives. During storage, samples stored in nitrogen showed the highest carotenoid retention (97–100%). The carotenoid retention in powders stored with air access varied between 12.3% ± 2.1% and 66.0% ± 5.4%, having been affected by the particle structure as well as the formulation components used. The comparative evaluation of the tested strategies allows a more targeted design of processing and formulation of functional carrot concentrate powders.

Effect of freeze-drying and air-drying on the content of carotenoids and anthocyanins in stored purple carrot.

In stored freeze-dried orange carrots, carotenoids are not stable compounds. The aim of the work was to evaluate the stability of carotenoids in products obtained from polyphenol-rich purple carrots which additionally contain anthocyanins. This study compares the effect of air-drying and freeze-drying as well as 6-month storage on the content of carotenoids, anthocyanins and total phenolics in dried products obtained from purple carrot. The phenolic compounds found in the greatest amounts in carrot were ferulic acid cyanidin 3-xylosylglucosylgalactoside, p-coumaric acid cyanidin 3-xylosylglucosylgalactoside, chlorogenic acid, and caffeic-quinic acid. Freeze-drying did not significantly reduce levels of carotenoids and anthocyanin content, while air-drying led to substantial losses of carotenoids, anthocyanins and polyphenols. 6-month storage of freeze-dried products caused losses of carotenoids, anthocyanins and total polyphenols of 42%, 33% and 53% respectively when compared with the raw material. In air-dried products, the losses were 66%, 33% and 36%, respectively. The results indicate that the combined effect of freeze-drying and 6-month storage was reduced losses of carotenoids compared to traditionally dried products.

Effect of Thermal Processing on Carotenoids and Folate Changes in Six Varieties of Sweet Potato (Ipomoes batata L.).

Carotenoids and folate are two mandatory supplying micronutrients for children or pregnant women. Inadequate intake of these two nutrients was relevant to a higher mortality of both children and pregnancies. This study is intended to investigate the thermal impact on the changes of carotenoids and folate in sweet potato roots (SPRs). Carotenoids were identified by high performance liquid chromatography (HPLC) while the folate was estimated using a microbial assay. An obvious decline was observed in total carotenoids after heating. Nevertheless, the content of provitamin compound β-carotene exhibited incredible stability during steaming and α-carotene multiplied in certain varieties, evidencing that SPRs could be an efficient way for addressing Vitamin A deficiency (VAD). As for the total folate contents, two varieties were found no significant loss after thermal process while the others showed a significant decrease. The results indicated that steaming process led to generally loss of both carotenoids and folate while the α-carotene and β-carotene were well preserved. The information provided by this study might help with enhancing the food quality in processing industry and the understanding in the nutrition changes during steaming.

Effect of boiling on bioactive compounds and radical scavenging activity of anthocyanin-rich vegetables: Red amaranth and red skin potato

This study was conducted to determine the optimum boiling time resulting in maximum retention of the bioactive compounds and radical scavenging activity. For this analysis, two most commonly consumed anthocyanin-rich vegetables , red amaranth (Amaranthus tricolor) and red skin potato (Solanum tuberosum) were exposed to boiling for 0, 1, 5, 10, and 20 minutes. Then the effects of boiling times on physicochemical, bioactive compounds, and antioxidant activity by DPPH radical scavenging ability were analyzed. In physicochemical analysis, ash content was decreased significantly, and the pH value increased significantly as the boiling time increased (p<0.05). The % of WSI was increased significantly as the boiling time for red amaranth as well as red skin potato (p<0.05) increased. The total polyphenol content (TPC), total anthocyanin content (TAC), total carotenoid content (TCC), and radical scavenging activity (RSA) of red amaranth and red skin potatoes were gradually reduced with the increasing of boiling time. The first - order kinetic model showed the good fit for the loss of total phenolic, carotenoids, anthocyanin, and DPPH radical scavenging activity of red amaranth and red skin potatoes with 0.86 - 0.98 coefficient of determination (R2). The findings could encourage both the household boiling and the food industry to recommend specific boiling time to maintain vegetables' antioxidant properties.

Effect of different grape residues polyphenols impregnation techniques in mango

The objective of this work was to evaluate the effect of the incorporation of grape residue polyphenols in mango using different impregnation methods. Experiments were performed at atmospheric pressure or vacuum, and with or without performing osmotic treatment and ultrasound. The samples were evaluated after the different impregnation techniques in terms of carotenoids, phenolic compounds, ascorbic acid, energy consumption, color, and firmness. The osmotic dehydration assisted impregnation showed positive results in relation to the incorporation of polyphenols in the mango (3.22–3.34 mg GAE/g DM), but negative in relation to carotenoids (27.37–32.71 μg/g DM) and ascorbic acid (11.90–16.22 mg/100 g DM), while the use of ultrasound showed results satisfactory in all evaluated parameters. The combination of ultrasound and osmotic dehydration in the impregnation resulted in samples with higher losses of carotenoids (28.8–29.38 μg/g DM), small incorporation of phenolic compounds (2.21–2.54 mg GAE/g DM) and retention of ascorbic acid (21.34–22.32 mg/100 g DM). Although the total energy expenditure was higher (0.05–0.09 kWh), the vacuum impregnation and ultrasound-assisted vacuum impregnation assays presented the best performance in relation to the retention of carotenoids (33.07–34.53 μg/g DM) and ascorbic acid (28.29–40.97 mg/100 g DM), greater incorporation of polyphenols from the grape residue by mango (6.29–7.74 mg GAE/g DM), greater color change due to the presence of grape residue extract, and softer texture when compared to untreated samples.

Loss of carotenoids from membranes of Pantoea sp. YR343 results in altered lipid composition and changes in membrane biophysical properties

Bacterial membranes are complex mixtures of lipids and proteins, the combination of which confers biophysical properties that allows cells to respond to environmental conditions. Carotenoids are sterol analogs that are important for regulating membrane dynamics. The membrane of Pantoea sp. YR343 is characterized by the presence of the carotenoid zeaxanthin, and a carotenoid-deficient mutant, ΔcrtB, displays defects in root colonization, reduced secretion of indole-3-acetic acid, and defects in biofilm formation. Here we demonstrate that the loss of carotenoids results in changes to the membrane lipid composition in Pantoea sp. YR343, including increased amounts of unsaturated fatty acids in the ΔcrtB mutant membranes. These mutant cells displayed less fluid membranes in comparison to wild type cells as measured by fluorescence anisotropy of whole cells. Studies with artificial systems, however, have shown that carotenoids impart membrane rigidifying properties. Thus, we examined membrane fluidity using spheroplasts and vesicles composed of lipids extracted from either wild type or mutant cells. Interestingly, with the removal of the cell wall and membrane proteins, ΔcrtB vesicles were more fluid than vesicles made from lipids extracted from wild type cells. In addition, carotenoids appeared to stabilize membrane fluidity during rapidly changing temperatures. Taken together, these results suggest that Pantoea sp. YR343 compensates for the loss of carotenoids by changing lipid composition, which together with membrane proteins, results in reduced membrane fluidity. These changes may influence the abundance or function of membrane proteins that are responsible for the physiological changes observed in the ΔcrtB mutant cells.

Incorporation and stability of carotenoids in a functional fermented maize yogurt-like product containing phytosterols

A functional yogurt-like product based on fermented maize enriched in carotenoids and phytosterols was developed to be an alternative to existing functional dairy products. Incorporation and stability of fat-soluble compounds were challenging in this complex matrix. Moreover, it is known that phytosterols decrease carotenoids absorption, but this decline can be offset by increasing carotenoids in foodstuffs. Thus, the aims of this work were to optimize the manufacturing process of a fermented yogurt-like product containing phytosterols by incorporating carotenoids taking into account two Lactobacilli strains as starters. The stability of β-cryptoxanthin, β-carotene and lycopene was studied during the whole process in order to confer a nutritional balance between them and phytosterols. After 15 h of fermentation, a starter ratio 50-50 (L. plantarum-L. casei) gave the best final biomass with 109 CFU/g necessary to obtain a probiotic potential. Relative carotenoid losses (20–27%) occurred during the pasteurization step while no negative impact on carotenoids was due to fermentation. Fat-soluble compounds remained relatively stable during the whole process with 75% of retention. These results suggest that incorporation and stability of carotenoids in a fermented-maize yogurt-like product containing phytosterols are necessary steps to induce a cholesterol-lowering effect without detrimental effects on carotenoids.

Effect of Processing Methods on the Physicochemical, Mineral and Carotene Content of Orange Fleshed Sweet Potato (OFSP)

The effect of processing methods on the physiochemical, mineral, vitamin C and carotenoid content of orange fleshed sweet potatoes were investigated. The processing methods used were boiling, steaming, roasting, frying and microwaving. The result of the proximate composition showed that the roasted orange fleshed sweet potatoes (OFSP) had the highest ash content ranging from 0.32-0.99%, crude protein 0.96-3.12%, crude fiber 0.50-3.40% and carbohydrate content 13.98-40.10% with a decrease in the moisture content from 83.10% - 49.25%. Fat content of the fried OFSP ranging from 0.96-6.01% was higher than the other samples. Steaming method enhanced the vitamin C content of the OFSP when compared to other processing method, while carotenoid losses were higher after frying 2.59mg/g, than after microwaving 3-91%, roasting 4.73mg/g, boiling 4.60mg/g and steaming 2.68mg/g. Mineral analysis showed that the boiled orange flesh sweet potatoes (OFSP) had zinc, copper and magnesium content higher than the other heat treated samples with 6.21mg/g, 4,164mg/100g and 479.88mg/100g respectively. Sensory analysis results showed that there were no significant (p&amp;lt;0.05) differences in the sensory scores of the orange-fleshed sweet potatoes. The study therefore showed that roasting and frying made available more protein, fat, ash and carbohydrate content, while boiling made available more minerals.

HPLC-UV/Vis-APCI-MS/MS Determination of Major Carotenoids and Their Bioaccessibility from "Delica" (Cucurbita maxima) and "Violina" (Cucurbita moschata) Pumpkins as Food Traceability Markers.

Carotenoids are a widespread group of fat-soluble pigments, and their major nutritional importance comes from their pro-vitamin A activity and their antioxidant capacity. In this study, two different pumpkin cultivars (Cucurbita maxima, also named ‘Delica’ and Cucurbita moschata, also known as ‘Violina’) from the southern Po Delta area were investigated in terms of carotenoid content and the influence of food processing on compositional changes and carotenoid bioaccessibility. Quali- and quantitative determination of carotenoids in sample extracts were performed on a C30 column by means of an online coupled HPLC-UV/Vis-APCI-MS/MS technique. The identification of separated compounds was tentatively achieved by merging (i) chromatographic data, (ii) UV-Vis spectra, and (iii) MS/MS fragmentation spectra. The chromatographic profiles for the two cultivars showed qualitative differences. Two major carotenoids were considered for quantification purposes and further investigations: lutein and -carotene. Quantification of target carotenoids was performed with external calibration through analytical standards. The concentration of lutein and -carotene was higher in C. maxima than in the other variety, C. moschata. Carotenoids are susceptible to degradation (isomerization and oxidation) during food processing (i.e., cooking), and the concentration of lutein and -carotene were monitored in oven-cooked and steam-cooked pumpkins. The steam-cooking process was superior in terms of limiting carotenoid loss. A complete functional profile of pumpkins as a source of carotenoids was gained with the evaluation of their in vitro bioaccessibility and their bioavailability after intake during human digestion. Bioaccessibility of lutein and -carotene were estimated by an in vitro static digestion model that involved salivary, gastric, and duodenal phases. Bioaccessibility values progressively increased from the salivary to the duodenal phase for both pumpkin varieties and cooking methods. Bioaccessibility of lutein was always lower than -carotene for both cultivars and for both cooking methods. Bioaccessibility values for lutein and -carotene changed from 1.93% to 2.34% vs. 4.94% and 8.83% in the salivary phase, from 2.7% to 4.63% vs. 7.83% and 15.60% in the gastric phase, and from 10.04% to 13.42% vs. 25.81% and 35.32% in the duodenal phase. For both target compounds, bioaccessibility in the duodenal phase was more than twice the gastric values, and it underlined that the type of cooking did not influence release from the initial matrix.

Effect of edible coating on shelf life and quality of local mango cv. Rangkuai of Mizoram

Highly nutritious, delicious and attractive looking fruits of mango which are generally consumed fresh undergo high amount of post-harvest losses. An experiment was taken up to study the impact of different edible coatings viz., olive oil, wax, chitosan, carboxy methyl cellulose, aloe gel on shelf life and quality of local mango cv. Rangkuai collected from Saiha district of Mizoram; kept in ambient condition. Results of the experiment showed that fruit coated with wax remained dark green skin colour (L: 28.73, a: -18.55, b: 26.03) and pulp colour was slightly yellowish orange (L: 63.69, a: -2.38, b: 60.78), whereas fruit skin colour at control had slightly light green colour with yellowness (L: 35.87, a: -18.88, b: 38.58) with completely dark orange colour pulp (L: 44.21, a: 23.32, b: 52.34) at 12 days after storage (DAS). Waxed mango fruits had minimum weight loss (1.18%) and high amount of ascorbic acid (19.92 mg/100 g) and carotenoids (4.64 mg/100 g) even after 12 DAS. Maximum shelf life was observed in waxed mango (19.65 days) as the fruit decay was only 10.05%.

Comparative Study on the Zinc and Cadmium Tolerance Potential of Twelve Prominent Rice Cultivars

Heavy metal pollution being a potential threat to agriculture raising rice cultivars with heavy metal tolerance is a promising strategy for remediation of heavy metal polluted agricultural lands. We present here a comprehensive study describing the differences in physiological and biochemical responses of 12 prominent high-yielding rice cultivars to increasing ZnSO4 concentrations (0, 2, 6, and 10 mM) and CdCl2 concentrations (0, 1, 2, and 3 mM). Even though Zinc (Zn) is an essential element required for the normal growth and development process of plants, a higher concentration of Zn has an antagonistic effect. Cadmium (Cd) is detrimental to plants and is found in soils contaminated with heavy metals. The effects of Zn and Cd on rice seedlings were a reduction in shoot length, greater chlorophyll and carotenoid loss, higher malondialdehyde content, proline accumulation, and an increased level of sugar and amino acids when treated with CdCl2 and ZnSO4. The CdCl2 and ZnSO4 stress-induced biochemical changes displayed major differences in the 12 rice cultivars in terms of tolerance to Zn and Cd toxicity. Our data provides evidence that the cultivar Varsha showed the highest tolerance and cultivar JY showed the least tolerance towards Cd and Zn toxicity.

Development of healthy crispy carrot snacks using sequential infrared blanching and hot air drying method

Sequential infrared (IR) blanching and hot air (HA) drying is a sustainable technology with high processing and energy efficiency. To develop a healthy crispy carrot snack, the carrot slices were blanched with IR at different intensities followed by HA drying at different temperatures. The results showed that IR blanching reduced the drying time at 60, 70 and 80 °C by 32.3%, 41.1% and 45.0%, respectively, and produced redder and crispier products with less residual peroxidase (POD) activity, compared to the treatments without blanching. In addition, the sequential IR blanched and HA dried carrot chips had 14.39%, 19.66% and 19.03% higher vitamin C contents than unblanched HA dried chips at 60 °C, 70 °C and 80 °C, respectively. IR blanching resulted in lower total carotenoid loss of the dried carrot samples. The optimal conditions for drying carrot chips were IR heating at 552 W power for 110 s by placing the samples at 70 mm from the emitter, for IR blanching, followed by HA drying at 80 °C for 45 min. In summary, sequential IR blanching and HA drying has a potential application in producing carrot snacks with improved sensory and nutritional quality.

Influence of ultrasound and vacuum assisted drying on papaya quality parameters

The aim of this study was to evaluate the combination of ultrasound and vacuum on papaya drying kinetics and some quality parameters. Drying was performed at 60 °C and four techniques were used: ultrasound and vacuum assisted drying (USVD), vacuum drying (VD), ultrasound assisted drying (USD) and control (without ultrasound and vacuum) drying (CD). Fresh and dried samples were evaluated in terms of color, texture, total carotenoid and ascorbic acid contents. USVD papaya had lower processing time, requiring 270 min to reach the dynamic equilibrium condition, while CD papaya required 450 min. The samples that presented the lowest loss of ascorbic acid (41.3%) were those dried with the aid of ultrasound and vacuum, while USD samples showed lower carotenoid loss after processing (9.7%). All dried samples had a reduced luminosity and yellow color and an increase in red tone. In relation to texture, CD sample had the highest hardness value, while USVD dried sample presented the lowest value. Ultrasonic treatment accelerated the vacuum drying process for papaya and minimized the loss of the bioactive compounds studied and products' color.

Biochemical characterization of blackberry fruit (Rubus sp) and jellies

The present study aimed to quantify the phenolic compounds, carotenoids, anthocyanins and antioxidant activity using 2 different methods in blackberry fruits harvested at 3 different harvest points along the storage time and jellies made from these fruits and the quantification of ascorbic acid in the fruits. The harvesting points used were defined visually, being: 100% red (T1); 50% red and 50% black (T2) and 100% black (T3). After harvest, the fruits were selected, washed and packed in PET boxes with capacity for 200g of fruit and stored for 15 days at 2 degreesC, being evaluated every 3 days and for the manufacture of the jellies, the fruits were first pulped in stainless steel pulping machine being the jellies prepared with 50:50 (fruit: commercial crystal sugar) in open pan. The results show that the loss of phenolic compounds, anthocyanins and carotenoids was small when fruits and jelly were compared, as well as the antioxidant activity, and this shows that the processing of this fruit does not cause losses in relation to these evaluated parameters.

Physical losses could partially explain modest carotenoid retention in dried food products from biofortified cassava.

Gari, a fermented and dried semolina made from cassava, is one of the most common foods in West Africa. Recently introduced biofortified yellow cassava containing provitamin A carotenoids could help tackle vitamin A deficiency prevalent in those areas. However there are concerns because of the low retention of carotenoids during gari processing compared to other processes (e.g. boiling). The aim of the study was to assess the levels of true retention in trans–β-carotene during gari processing and investigate the causes of low retention. Influence of processing step, processor (3 commercial processors) and variety (TMS 01/1371; 01/1368 and 01/1412) were assessed. It was shown that low true retention (46% on average) during gari processing may be explained by not only chemical losses (i.e. due to roasting temperature) but also by physical losses (i.e. due to leaching of carotenoids in discarded liquids): true retention in the liquid lost from grating negatively correlated with true retention retained in the mash (R = -0.914). Moreover, true retention followed the same pattern as lost water at the different processing steps (i.e. for the commercial processors). Variety had a significant influence on true retention, carotenoid content, and trans-cis isomerisation but the processor type had little effect. It is the first time that the importance of physical carotenoid losses was demonstrated during processing of biofortified crops.

Effect of a physical pre-treatment and drying on carotenoids of goji berries (Lycium barbarum L.)

In order to evaluate the influence of an abrasive pre-treatment and drying at 50 °C, 60 °C, 70 °C of goji fruits (Lycium barbarum L.), changes in colour and carotenoids were studied. An extraction method was modified and adapted to assay the main carotenoid esters and saponified carotenoids of goji berries, before and after treatments. Goji berries were confirmed as a high source of zeaxanthin, with zeaxanthin-dipalmitate at about 2 g/kg dry weight. The reliability of the analytical method was confirmed by the high quantitative recoveries, about 100%, a higher repeatability than reference methods and a good reproducibility (lower than 5%). After drying, significant but small carotenoid losses (15–20%) were observed in both pre-treated and treated samples. The xanthophyll esters confirmed to be more stable than free carotenoids. The drying process significantly modified colour, in both pre-treated and untreated samples, however, pre-treatment reduced drying time and thus better preserved the colour of the goji berries for a drying temperature up to 60 °C.