Retention Of Bioactive Compounds Research Articles

Preservation of bioactive compounds of a green vegetable smoothie using short time-high temperature mild thermal treatment.

Smoothies represent an excellent and convenient alternative to promote the daily consumption of fruit and vegetables in order to obtain their health-promoting benefits. Accordingly, a green fresh vegetables smoothie (77.2% cucumber, 12% broccoli and 6% spinach) rich in health-promoting compounds was developed. Soluble solids content, pH and titratable acidity of the smoothie were 4.3 ± 0.4°Bx, 4.49 ± 0.01 and 0.22 ± 0.02 mg citric acid 100-1 g fw, respectively. Two thermal treatments to reduce microbial loads and preserve quality were assayed: T1 (3 min at 80 ℃) and T2 (45 s at 90 ℃). Fresh blended unheated samples were used as control (CTRL). The smoothie presented a viscoelastic behaviour. T1 and T2 treatments reduced initial microbial loads by 1.3-2.4 and 1.4-3.1 log units, respectively. Samples were stored in darkness at 5 and 15 ℃. Colour and physicochemical changes were reduced in thermal-treated samples throughout storage, which were better preserved at 5 ℃ rather than at 15 ℃. Vitamin C changes during storage were fitted with a Weibullian distribution. Total vitamin C losses of T1 and T2 samples during storage at 15 ℃ were greatly reduced when they were stored at 5 ℃. Initial total phenolic content (151.1 ± 4.04 mg kg-1 fw) was 44 and 36% increased after T1 and T2 treatments, respectively. The 3-p-coumaroyl quinic and chlorogenic acids accounted the 84.7 and 7.1% relative abundance, respectively. Total antioxidant capacity (234.2 ± 20.3 mg Trolox equivalent kg-1 fw) remained constant after the thermal treatments and was better maintained during storage in thermal-treated samples. Glucobrassicin accounted the 81% of the initial total glucosinolates content (117.8 ± 22.2 mg kg-1 fw) of the smoothie. No glucosinolates losses were observed after T2 treatment being better preserved in thermal-treated samples. Conclusively, a short time-high temperature mild thermal treatment (T2) showed better quality and bioactive compounds retention in a green fresh vegetable smoothie during low temperature storage.

Ohmic heating and pulsed vacuum effect on dehydration processes and polyphenol component retention of osmodehydrated blueberries (cv. Tifblue)

Abstract Blueberries are highly perishable fruits; therefore, emerging technologies focus on improving the bioactive compound retention and extending the shelf life. The aim of this study was to evaluate the effect of ohmic heating and vacuum pulses on the dehydration processes and polyphenol compound retention of osmodehydrated blueberries (cv. Tifblue). The treatments were performed using a 65% (w/w) sucrose solution, an electric field of 13 V/cm (100 V) at 30 °C, 40 °C or 50 °C for 300 min, and air drying at 50, 60 or 70 °C to obtain dried blueberries. The moisture content, soluble solids and phenolic compounds were analyzed. The combination of ohmic heating/pulsed vacuum treatments intensifies mass transfer in osmodehydrated blueberries, especially at higher temperatures. Nevertheless, the polyphenol retention was greater at lower temperatures; hence, the application of an intermediate process temperature (40 °C) was selected as a pre-treatment prior to further drying. The treated samples improve the retention of polyphenols after drying compared with untreated samples. Therefore, the results of this research study suggest that the use of a pulsed vacuum and ohmic heating in the osmotic dehydration (PVOD/OH) treatment at 40 °C for 240 min and subsequent drying at 60°C could be the best process for dehydrating blueberries, considering that it improved mass transfer, achieved lower losses of phenolic components and reduced the drying time. Industrial relevance Blueberries are an important fruit due their high bioactive compound content, especially polyphenols. Studies that involve emerging technologies application could add value to blueberries. Ohmic heating and pulsed vacuum as pre-treatments improve the efficiency of dehydration processes, focused toward bioactive compounds retention and achieving commercial viability. In this work have been applied PVOD/OH treatments at moderated temperatures and subsequently dried at 60 °C, obtaining promissory results.

Biopolymer-prebiotic carbohydrate blends and their effects on the retention of bioactive compounds and maintenance of antioxidant activity

The objective of this study was to evaluate the use of inulin (IN), a prebiotic carbohydrate without superficial activity, as an encapsulating matrix of lipophilic bioactive compounds. For achieving the encapsulation, IN was associated with biopolymers that present superficial activity: modified starch (HiCap), whey protein isolate (WPI) and gum acacia (GA). Encapsulation was performed through emulsification assisted by ultrasound followed by freeze-drying (FD) process to dry the emulsions. All blends retained geranylgeraniol. GA-IN blend yielded the highest geranylgeraniol retention (96±2wt.%) and entrapment efficiency (94±3wt.%), whilst WPI-IN blend yielded the highest encapsulation efficiency (88±2wt.%). After encapsulation, composition of geranylgeraniol in the annatto seed oil was maintained (23.0±0.5g/100g of oil). Such findings indicate that the method of encapsulation preserved the active compound. All blends were also effective for maintaining the antioxidant activity of the oil through ORAC and DPPH analyses.

Delivery of Flavonoids and Saponins from Black Bean (Phaseolus vulgaris) Seed Coats Incorporated into Whole Wheat Bread.

Cereal-based products can be used as vehicles for the delivery of relevant bioactive compounds since they are staple foods for most cultures throughout the world. The health promoting benefits of flavonoids and saponins contained in black bean seed coats have been previously described. In the present work, the effect of adding flavonoids and saponins from black bean seed coat to the typical yeast-leavened whole wheat bread formulation in terms of bread features, organoleptic properties and phytochemical profile was studied. The retention of bioactive compounds was determined and the inhibitory effects of in vitro enzyme digested samples on two colon cancer cell lines (Caco-2 and HT29) was evaluated. The addition of bioactive compounds did not significantly affect baking properties or texture parameters. Among organoleptic properties of enriched breads, only crumb color was affected by the addition of bioactive compounds. However, the use of whole wheat flour partially masked the effect on color. More than 90% of added flavonoids and saponins and 80% of anthocyanins were retained in bread after baking. However, saponins were reduced more than 50% after the in vitro enzyme digestion. The black bean seed coat phytochemicals recovered after in vitro enzyme digestion of enriched breads significantly reduced by 20% the viability of colon cancer cells without affecting standard fibroblast cells (p < 0.05).

High Pressure Processing Induced Changes in Bioactive Compounds, Antioxidant Activity, Microbial Safety and Color Attributes of Coriander Paste

An attempt was made to quantify the effect of high pressure processing (HPP) (at 50, 200, 400 and 600 MPa) and thermal processing (90 °C) on bioactive compounds and microbial safety of coriander paste. Total soluble solids (TSS) and pH of untreated coriander paste was 7.8 and 6.21°brix, respectively. No significant (α = 0.05) difference was observed in pH or TSS after processing and during storage. Phenolic content increased by 0.99 and 1.10 % when treated at 400 and 600 MPa, respectively. Flavonoid content in high pressure (HP) processed (≥400 MPa) sample was significantly (α = 0.05) higher than thermally processed sample. The untreated coriander paste had ascorbic acid content of 1.32 mg/g which decreased to 1.17 and 0.50 mg/g on HP (600 MPa) and thermal processing, respectively. Chlorophyll a decreased from 1.68 mg/g to 1.58 and 1.21 mg/g in HP (600 MPa) and thermally processed sample, respectively. Complete enzyme [Polyphenol Oxidase (PPO) and Peroxidase (POD)] inactivation was observed after thermal processing, whereas pressure ≥400 MPa required to reduce enzyme activity significantly (α = 0.05). Lightness L* value decreased significantly (α = 0.05) with pressure. Total plate count reduced from 3.0 × 103 CFU/g to zero and 1 × 101 CFU/g in thermally and HP processed (600 MPa) samples, respectively. Storage study (at 4 °C for 45 days) showed that bioactive compounds and antioxidant activity in both thermally and HP processed samples decreased during storage, but this decrease was more severe in thermally processed samples. Thus, study reveals that HPP is more effective at ≥400 MPa, in terms of retention of bioactive compounds, than the thermal processing.

Osmo-dehydration of Plums and Berries - A Review

The influence of different osmotic dehydration methods on morphological and nutritional attributes of plums and berries has been reviewed and presented in this review. Several researches have been done for retention of bioactive compounds varying osmotic conventionally drying solution, brix, critical moisture content, drying temperature, drying time and methodology of osmotic dehydration process. Osmotic dehydration is a counter flow process which results in solids gain or impregnation, enhancing the textural and rheological properties of plum and related fruits. Osmotically dehydrated plums require less drying time than which results into improved overall quality. Reviews suggested that various osmotic agents with low molecular weight lead to higher water loss. Osmotic dehydration improves the overall quality of plums and berries as compared to the conventional drying methods.

Optimization of Spirulina sp. Drying in Heat Pump: Effects on the Physicochemical Properties and Color Parameters

The aim of this work was to optimize the drying operation of Spirulina sp. using the heat pump to dehumidify the air. An experimental design using the drying air temperature (30, 40 and 50C) and the initial sample thickness (1, 3 and 5 mm) was performed. The responses were the physicochemical properties and the color parameters of the dried microalgae. The air temperature presented the highest effect on the phycocyanin content, while the sample thickness showed the highest influence on the other responses. The optimal operating conditions for the heat pump drying of Spirulina sp. were at air drying temperature of 50C and sample thickness of 5 mm. The phycocyanin content, total antioxidant activity and color difference were found to be 19.60 mg/g, 52.6% and 5.71, respectively. Thermograms (differential scanning calorimetry) showed that under these conditions, the product showed the highest thermal stability. Practical Applications The culture of Spirulina sp. is attractive for various commercial purposes, such as nutritional supplement for humans and animals and supply of active metabolites in the pharmaceutical and cosmetic industry. The conventional tray drying is a traditional method that is used in the microalgae drying. However, the heat pump drying enables operation in lower temperatures than the traditionally used in convective hot air drying. This operation occurs in moderate conditions of temperature and humidity due to air dehumidification, leading to retention of bioactive compounds in products that are heat sensitive. Therefore, the use of heat pump dryer for the production of dried Spirulina should be promising to preserve its phytochemicals and physical characteristics. The benefits of heat pump drying have been shown in different studies in the literature, but there are no reports about its use in Spirulina drying and its influence on the physicochemical and functional characteristics.

Effect of the intensity of cooking methods on the nutritional and physical properties of potato tubers

The different intensities of common culinary techniques (boiling, baking and microwaving) produce several changes that reduce the nutritional and physical properties of potatoes. This study evaluated the effect of those cooking methods on the quality of commercial potato tubers (Agata, Kennebec, Caesar and Red Pontiac). The higher weight losses were obtained for baking, but the potato softening depended on the cultivar. Color losses were independent of the intensity of the treatment; however, microwaving promoted a prompt starch gelatinization with respect to the other methods. The resistant starch retention of baking and microwaving was higher than that of boiling, and the maximum retention of bioactive compounds was obtained with the lower core temperature during boiling, as well as higher temperature and shorter baking time and the lower power and longer microwaving time. Principal component analysis revealed significant relationships between the instrumental and functional properties of cooked potatoes.

Effect of Initial Temperature Treatment on Phytochemicals and Antioxidant Activity of Azadirachta indica A. Juss.

The present study was undertaken to evaluate the effect of initial temperature treatment on phytochemical and antioxidant potential of commercially important plant Azadirachta indica A. Juss. The leaves were differentially treated after harvest at temperatures 4, -20, and 110°C and at room temperature, separately. It was found that a quick drying process at 110°C followed by air-drying helped in maximum retention of bioactive compounds and antioxidant activity, which was significantly higher than other processing methods. Correlation analysis revealed that total phenolic content (TPC) and total flavonoid content (TFC) can be a measure to assess the antioxidant potential using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing/antioxidant power (FRAP) assays. Nitric oxide scavenging assay (NOSA) was insignificantly related to DPPH and FRAP. Also, FRAP and DPPH can be a predictive assay for each other, but not with NOSA. Thus, a quick drying process at 110°C using an oven can be a cost-effective venture, especially in developing countries, for retaining the nutritive value and antioxidant activity of A. indica.

Effect of frozen storage on polyphenol content and antioxidant activity of haskap berries (Lonicera caerulea L.)

BACKGROUND: Haskap berries (Lonicera caerulea L.) are processed into various products (e.g. juice, jam and chutneys). These fruits are rich in bioactive compounds, though losses can occur during frozen storage, affecting the nutritional content of the products. OBJECTIVE: To investigate the effect of freezing storage temperature (–18 and –32 ◦ C) and steam blanching prior to freezing on the the total phenolic content (TPC)/total reducing capacity (TRC), total anthocyanin content (TAC) and antioxidant potential of three Haskap berry varieties; Tundra (T), Berry Blue (BB) and Indigo Gem (IG). METHODS: Berries were stored at –18 or –32 ◦ C for six months, and analyzed monthly for TPC/TRC, TAC, and DPPH radical scavenging activity. Steam blanching prior to freezing was also evaluated. RESULTS: Frozen storage at –18 ◦ C for six months reduced the TPC/TRC by 37.08 to 47.16%. TAC was also reduced, where the highest decrease was for BB (59.24%) followed by IG (46.34%), and DPPH scavenging activity decreased by 26.78 to 30.86%. Blanching prior to freezing improved the retention of bioactive compounds but storage at –32 ◦ C did not yield significant improvements. CONCLUSIONS: Steam blanching prior to freezing followed by frozen storage at –18 ◦ C is recommended for better retention of the bioactive components of haskap berries.

Production of maize tortillas and cookies from nixtamalized flour enriched with anthocyanins, flavonoids and saponins extracted from black bean (Phaseolus vulgaris) seed coats

Ethanolic extract from black beans coat is a source of flavonoids, saponins and antocyanins. Nixtamalized maize flours (NF) are used for the preparation of products such as tortillas, tortillas chips, cookies among others. The objective of this research was to study the effect on textural parameters and color after adding flavonoids, saponins and anthocyanins from black bean seed coat in NF used for the production of tortillas and gluten-free cookies. Furthermore, the retention of bioactive compounds after tortilla and gluten-free-cookie preparation was assessed. Ethanolic extracts of black bean seed coats were added (3g/kg or 7g/kg) to NF in order to prepare corn tortillas and gluten free cookies characterized in terms of dimensions, color and texture. Addition of 7g/kg affected the color of cookies and tortillas without effect on texture and dimensions. It was possible to retain more than 80% and 60% of bioactives into baked tortillas and cookies, respectively.

Effect of Thawing Conditions on Polyphenol Content and Antioxidant Activity of Frozen Haskap Berries (Lonicera caerulea L.)

The effect of different thawing methods on three haskap berry (Lonicera caerulea L.) varieties, Tundra (T), Berry Blue (BB) and Indigo Gem (IG), was investigated. Methods included thawing the frozen berries at room temperature (25 ± 2 °C), refrigerated temperature (4 °C) and using a microwave oven. All the berry varieties were analyzed for their total phenolic content (TPC)/total reducing capacity (TRC), total anthocyanin content (TAC) and antioxidant potential (DPPH radical scavenging activity). The TPC/TRC, TAC and DPPH scavenging activity ranges in the fresh fruits were 6.17-8.42 mg GAE/ g FW, 4.49-6.97 mg C-3-G E/ g FW, and 78.70-89.55 %, respectively. Frozen storage for six months followed by consequent thawing at the standard conditions (room temperature) caused 35.85-44.73, 32.14-53.23, and 26.28-29.57 % reductions in the TPC/TRC, TAC, and DPPH scavenging activity, respectively. The highest reduction occurred in the Berry Blue variety followed by that of Indigo Gem. Refrigerated thawing did not significantly improve the retention of phenolic compounds and anthocyanins. Microwave thawing could be achieved in significantly shorter time (17.31 min) as compared to room temperature (12.00 h) and refrigerated thawing (22.00 h) and could significantly improve the retention of phenolics, anthocyanins and antioxidant potential. The corresponding reductions in the TPC/TRC, TAC, and DPPH scavenging activity of different varieties ranged from 24.97%-39.87%, 18.92%-47.22%, and 21.39%- 27.29 %, re-spectively. Thus, further investigation into the industrial application of microwave thawing is recommended to maximize the retention of bioactive compounds in products manufactured from frozen haskap berries. Keywords: Haskap berry, Lonicera caerulea, freezing, thawing, polyphenols, antioxidant activity.

Effect of Extrusion Cooking on Bioactive Compounds in Encapsulated Red Cactus Pear Powder

Red cactus pear has significant antioxidant activity and potential as a colorant in food, due to the presence of betalains. However, the betalains are highly thermolabile, and their application in thermal process, as extrusion cooking, should be evaluated. The aim of this study was to evaluate the effect of extrusion conditions on the chemical components of red cactus pear encapsulated powder. Cornstarch and encapsulated powder (2.5% w/w) were mixed and processed by extrusion at different barrel temperatures (80, 100, 120, 140 °C) and screw speeds (225, 275, 325 rpm) using a twin-screw extruder. Mean residence time (trm), color (L*, a*, b*), antioxidant activity, total polyphenol, betacyanin, and betaxanthin contents were determined on extrudates, and pigment degradation reaction rate constants (k) and activation energies (Ea) were calculated. Increases in barrel temperature and screw speed decreased the trm, and this was associated with better retentions of antioxidant activity, total polyphenol, betalain contents. The betacyanins k values ranged the −0.0188 to −0.0206/s and for betaxanthins ranged of −0.0122 to −0.0167/s, while Ea values were 1.5888 to 6.1815 kJ/mol, respectively. The bioactive compounds retention suggests that encapsulated powder can be used as pigments and to provide antioxidant properties to extruded products.

Impact of the industrial freezing process on selected vegetables -Part II. Colour and bioactive compounds

In the present study, the impact of the different steps (i.e. blanching, freezing, storage following the industrial freezing process and the final cooking prior to consumption) of the industrial freezing process was evaluated on colour, chlorophylls, lutein, polyphenols and ascorbic acid content of asparagus, green beans and zucchini. In addition, the domestic boiling of raw samples was compared with the boiling of frozen storage vegetables.Results showed that the blanching treatment retained phytochemicals in all studied green vegetables and the frozen storage up to 2months did not negatively affected phytochemicals, in particular lutein and flavonoids in almost all samples. On the contrary, colour significantly changed during blanching and frozen storage. The changes of b* (yellowness) and the shift of H° (hue angle) were not coherent with the increase of pheophytin. In addition, the greenness (−a*) was found to increase with the exception of boiled samples in all vegetables. Generally, in boiled frozen vegetables there was a better or comparable retention of bioactive compounds with respect to raw ones, and this was especially true for green beans and zucchini. Colour changes after cooking did not exhibit the same trends among vegetables, being more remarkable for frozen asparagus in comparison with those boiled from raw, but overall comparable for green beans and zucchini.In conclusion, the overall results of the present study suggest that, when the industrial freezing process is well performed, the boiled frozen vegetables do not have a lower nutritional value than the fresh ones.

Effects of the spray-drying temperatures on the physiochemical properties of an encapsulated bitter melon aqueous extract powder

Bitter melon (Momordica charantia L.) is a medicinal fruit often used for the treatment of diabetes, due to its content of saponins, phenolics and flavonoids and its antioxidant capacity. The aims were to use response surface methodology (RSM) to optimise the inlet (125.6, 130, 140, 150, 154.1°C) and outlet (72.9, 75, 80, 85, 87.1°C) temperatures for the spray-drying encapsulation of a bitter melon aqueous extract using a combination of maltodextrin and gum Arabic as encapsulating agent and to determine the stability of the optimised encapsulated powder under various storage conditions. The RSM models were adequate to describe and predict the responses for the process yield, the retentions of saponins, phenolics, flavonoids and antioxidant activity, the moisture content and the water solubility index with an overall R2≥0.91. The optimal inlet and outlet temperatures were determined to be 140°C and 80°C, respectively. The optimised spray-dried powder had high values for process yield (71.4±1.4%), retention of bioactive compounds and antioxidant activity (≥87.9±2.6%), water solubility index (89.9±0.51%) and had a low moisture content (2.2±0.1%), which was below the Mo=5.71 predicted by the BET model. However, in terms of the morphology of the powder particles under scanning electron microscopy and loss of the bioactive compounds and antioxidant activity, the safest range for preserving the powder at 25°C was determined to range from 22.5% to 33.8%. The encapsulated powder was also slightly more stable at −20 and 10°C than at 30°C, over 150days. Therefore, it can be concluded that spray-drying with the inlet temperature at 140°C and the outlet temperature at 80°C resulted in a very stable encapsulated powder of the bitter melon aqueous extract.

Nutritional and antioxidant potential of canjiqueira fruits affected by maturity stage and thermal processing

The effect of jelly processing on the chemical properties, nutrients, antinutritional factors, bioactive compounds, and antioxidant activity of unripe and ripe canjiqueira fruits was evaluated. The fruits were collected from Pantanal regions at two different ripening stages and were used to produce jellies. The processing affected the chemical characteristics and the content of all nutrients, except for the lipids. Moisture and protein content reduced, whereas the energy value increased. The phytic acid found in fresh fruits was eliminated after processing, and the trypsin inhibitors were reduced, especially in ripe fruits. Lectin activity was not verified in unripe and ripe fruits and jellies. The levels of bioactive compounds were reduced after jelly processing, but their retention was higher in unripe fruits. The final levels of bioactive compounds in the jelly made from unripe fruits were higher than that in the jelly made from ripe fruits, whereas the IC50 value was lower, indicating higher potential to prevent free radicals damages to human body. Jelly processing proved to be a good alternative to the use of canjiqueira fruits due to the reduction in antinutritional factors and the retention of bioactive compounds

Effects of different defrosting methods on the stability of bioactive compounds and consumer acceptability of frozen broccoli

Broccoli (Brassica oleracea var. italica) is an excellent source of bioactive compounds. Frequently, it is commercialized frozen, though it has to be thawed before consumption. However, defrosting methods can affect the nutritional and sensory properties of broccoli. Therefore, the effect of defrosting (microwaving and boiling) for serving broccoli either cold or hot on the content of bioactive compounds (vitamin C, carotenoids, phenolic compounds, and glucosinolates) and sensory acceptability of frozen broccoli was studied. Marked losses of hydrosoluble compounds were observed after boiling. Carotenoids increased after short-time boiling (~20%) but dramatically decreased after microwave-defrosting (between 30% and 40% less). Nevertheless, short defrosting using microwave showed the less overall losses. Moreover, microwave-based methods were preferred by consumers. Microwave-defrosting of broccoli for a short period of time may be the method of choice for better retention of bioactive compounds and organoleptic properties.

Drying Method Affects Bioactive Compounds and Antioxidant Activity of Carrot

Dehydration of carrot (Daucus carota L.) is a method of preservation to make it available throughout the year. An investigation was carried out to study effects of hot air and freeze-drying on bioactive compounds and antioxidant activity in carrot slices. Carrot slices were pretreated with potassium metabisulphite (KMS) prior to drying. Hot-air drying of carrot slices was at 60 ± 5 °C; freeze-drying was at −30 °C. Dried carrot slices were analyzed for antioxidant activity by DPPH assay on the bioactive compounds total carotenoids, β-carotene, total phenolics, tannins, ascorbic acid and lycopene. Freeze-drying better retained antioxidant activity and bioactive compounds in carrot slices compared with hot-air drying. Sulphur dioxide in KMS, an antioxidative, beneficially affected retention of bioactive compounds during hot-air drying, but had negligible effects during freeze-drying. The rehydration ratio was higher in freeze-dried carrot slices compared with hot-air-dried carrot slices. During storage minimum loss occurred for KMS treated hot-air-dried carrot slices then by KMS treated freeze-dried, control freeze-dried and control hot-air-dried carrot slices. Sulphur dioxide as a pretreatment prior to hot-air drying beneficially retained bioactive compounds in carrot slices compared with freeze-drying.

Composition Profiles and Functional Properties of Dietary Fiber Powder from Lime Residues: Effects of Pretreatment and Drying Methods

Lime residues after juice extraction have proven to be a potential raw material for producing dietary fiber (DF) powder due to their good functional properties. Compositions and antioxidant activity of DF powder from lime residues as affected by selected pretreatment (hot-water blanching and ethanolic soaking) and drying methods, viz. hot air drying, vacuum drying, and low-pressure superheated steam drying (LPSSD) at 60–80°C, were investigated. Fresh lime residues contained significant amounts of vitamin C, phenolic compounds, and flavonoids. Hesperidin was a major flavonoid and only one polymethoxyflavone (i.e., tangeretin) was detected in small amounts. A decrease in the amount of interested bioactive compounds and their antioxidant activity was noted at almost all steps of processing. Higher retention of bioactive compounds was noted when the residues were subject either to vacuum drying or LPSSD; the total antioxidant activities were 61–62% and 81–82% when being assessed by the β-carotene bleaching and DPPH assays, respectively. Vacuum drying at 80°C was the most suitable condition for preparing DF powder from lime residues due to its short required drying time and its ability to retain bioactive compounds. The in vitro analyses imply that DF powder prepared by vacuum drying at 80°C has the potential to reduce blood glucose and cholesterol levels by exhibiting high glucose retardation index (GRI) and bile acid retardation index (BRI).

Effect of photo-selective nettings on post-harvest quality and bioactive compounds in selected tomato cultivars

Photo-selective coloured netting is referred to as a 'new agro-technological' concept adopted to manipulate light quality changes that can induce favourable responses in plants. Tomato (Solanum lycopersicum L.) cultivars AlvaV, Irit and SCX 248 grown under the black net (commercial net, 25% shading) showed higher weight loss, loss of firmness, ascorbic acid content and decline in the ratio of soluble solids content/titrable acidity during post-harvest storage (low-temperature storage at 10°C and 90% relative humidity for 21 days followed by market shelf conditions at 25°C for 2 days). During post-harvest storage, lycopene, β-carotene, total phenolic content and antioxidant scavenging activity were higher in cvs AlfaV and Irit grown under the black or pearl nets. However, the β-carotene, total phenolic content and antioxidant scavenging activity were higher in SCX 248 grown under the red net during post-harvest storage. Cultivar AlfaV grown under the red and pearl nets had a higher number of odour active aroma compounds during post-harvest storage. Panellists preferred cv. AlfaV grown under the pearl nets after storage based on taste, overall appearance and firm textured fruits. Pearl photo-selective nets retained the overall fruit quality and bioactive components in cvs AlfaV and Irit during post-harvest storage. Red photo-selective nets, however, showed greater influence on retention of overall fruit quality and bioactive compounds in cv. SCX 248 during post-harvest storage.