Instant Controlled Pressure-Drop (DIC) for Volatile Compound Extraction and Bioethanol Production from Empty Aleppo Pinecones and Eucalyptus Chips: Process Optimization and Statistical Modeling

Several plant species contain volatile compounds extracted as "essential oils" through different technologies. After essential oil extraction, the residual solid is a lignocellulosic solid waste. This work proposes the instant controlled pressure-drop (DIC) technology to autovaporize volatile compounds and modify the lignocellulosic matrix. Indeed, DIC technology is a thermomechanical process based on short-time/high-temperature and pressure pretreatment. It enhances the saccharification and fermentation process (SSF) for bioethanol production. A 3-variable design of experiments optimized the DIC processing parameters to reach 100% efficiency (EE) of volatile compound extraction using response surface methodology (RSM). Eucalyptus chips presented 50 volatile identified compounds after 7 min of DIC treatment. 1,8-Cineole, β-phellandrene, aromadendrene, eudesmol, and spathulenol are the most important volatile compounds. The empty Aleppo pinecones delivered 32 volatile compounds in 5 min of DIC treatment, the most important of which were caryophyllene, nortricyclene, verbenol, and camphor. After the autovaporization extraction stage, solid fraction residues were hydrolyzed and fermented in the same stirred bioreactor, using SSF strategy for 72 h at 37 °C. The highest bioethanol yields reached 73.9% and 54.82% (g per 100 g DM) from eucalyptus chip and empty Aleppo pinecone, respectively.

Optimization of DIC-Tripolium Ecofriendly Extraction Process: Recovery of Hesperidin from Orange Byproducts, Antioxidant and α-Amylase Inhibition of Extracts

This study aimed to investigate the effect of an innovative ecofriendly process-instant controlled pressure drop technology, also known as "détente instantanée contrôlée" or DIC-coupled with Tripolium extraction (DIC-Tripolium), on the hesperidin recovery, and antioxidant and antidiabetic activities of orange byproduct extracts. A DIC pretreatment was applied to partially dried orange byproducts (~16% wet basis). A central composite rotatable design (CCRD), composed of 13 experimental trials (four factorial points, four-star points, and five repetitions for the central point), was followed by a Tripolium process consisting of successive intermittent extraction periods using ethanol/water solvent at 20 ± 1 °C, 5 kPa for 5 min and m/v ratio = 5 g/50 mL. The DIC pretreatment, coupled with the Tripolium process, increased the extractability of hesperidin (from 1.55- to 4.67-fold compared to untreated DIC orange byproducts). The radical scavenging activities of the extracts were also enhanced or preserved in different DIC-Tripolium extracts. The α-Amylase inhibition percentage varied between 55.6 ± 0.02 and 88.30 ± 0.01% according to DIC-Tripolium conditions. The multi-criteria optimized condition of DIC-Tripolium extraction, allowing for the maximization of the hesperidin content, radical scavenging activities, iron chelating activity, and α-amylase inhibition of extracts, corresponds to a DIC saturated steam pressure of 599.4 kPa and a DIC pretreatment time of 38 s.

Use of instant controlled pressure drop technology for the preservation of edible insects' (yellow mealworm) quality: assessment of microbial inactivation

The world population is expanding, and with it, so is the need for proteins for the food and feed sectors. Conventional livestock production is correlated with negative environmental repercussions such as global warming, land degradation, and biodiversity loss. The nutritional content of edible insects is comparable to that of conventional meat, and insect farming offers various environmental advantages over livestock production, making it a favorable sustainable protein resource. However, to be placed on the market, insects should be processed, and their microbial load should be within the accepted range of the European Commission regulation (EU) 2021/882. The purpose of this research is to investigate the use of instant controlled pressure drop (DIC) technology for the microbial inactivation of yellow mealworm larvae. This innovative decontamination treatment was compared to blanching in hot water, the conventional processing method. We also investigated the impacts on enzymatic browning. Results showed that the application of rapid (20 s) DIC treatment at 0.3 MPa allowed reducing the total aerobic count and the total yeast and mold count of larvae below the thresholds authorized by the commission regulation. Pressure, temperature, and number of cycle factors were found to have significant effects on the decontamination, while the treatment time had no effect for most treatments. In regard to blanching, we were able to get the authorized load at 90 °C for 360 s. Decimal reduction times for DIC and blanching treatments were found to be 3.8 s and 67.8 s for total aerobic count, and 3 s and 57 s for total yeast and mold count, respectively. Furthermore, DIC-treated larvae showed a significant increase in juice color brightness, which could be traced back to the oxidative enzymatic inactivation of larvae, whereas there was a slight difference between blanched and untreated larvae juice colors.

A Preliminary Study on the Effect of the Instant Controlled Pressure Drop Technology (DIC) on Drying and Rehydration Kinetics of Maize Kernels (Zea mays L.)

Maize is one of the three worldwide cereal crops with the most outstanding production; however, its postharvest losses range from 2 to 40% due to inadequate harvesting, drying, and storage technologies. This study focuses on the Instant Controlled Pressure Drop technology (DIC) effect on maize kernels’ drying and rehydration kinetics. In total, 19 different DIC treatments were carried out on maize kernels (~25% d.b.). The DIC parameters studied were steam pressure (0.1 to 0.4 MPa) and treatment time (10 to 90 s). After DIC treatment, drying kinetics were carried out by Convective Air Drying (CAD) at 50 °C and 0.4 ms⁻¹ airflow. Rehydration kinetics and Water Holding Capacity (WHC) were evaluated at 20 °C. In comparison to CAD samples, DIC (0.4 MPa and 90 s) reduced the drying time from 180 min to ~108 min. Additionally, regarding the rehydration and WHC results, DIC achieved the same moisture content in only 3.5 min that controls achieved after 1 h of rehydration (0.40 g H₂O/g dry matter). Moreover, DIC (0.4 MPa and nine cycles of 10 s) increased the WHC 2.3 times compared to the control. In this way, DIC could be a postharvest technology to improve maize kernels’ drying operations and functional properties.

Optimisation of Instant Controlled Pressure Drop (DIC)-assisted dehydrofreezing using Response Surface Methodology towards better bioactive compounds retention of quince fruit

Pre-drying prior to freezing may reduce several freezing drawbacks. Nevertheless, drying may cause nutritional quality losses. Instant Controlled Pressure Drop process has been proposed to intensify pre-drying process. This research is dedicated to study the evolution of the main bioactive compounds (total phenolics, flavonoid, and tannins contents) of quince dehydrofrozen fruits. Fresh samples were subjected to air drying at 40 °C and 3 m s−1 air velocity down to a final water content of 0.3 g g−1 db. Pre-dried samples were Instant Controlled Pressure Drop (DIC) treated under different conditions, i.e. saturated steam pressure (P) and treatment time (t), following a 2-factor/5-level Experimental Design. Treated fruits were frozen at –30 °C then were thawed at 20 °C in order to study the impacts of DIC on phenolic compounds. Response Surface Methodology (RSM) confirmed that pressure was the most influencing parameter in terms of polyphenol, flavonoid, and tannins contents. Finally, DIC pre-treatment allowed the improvement of phenolic content retention compared to untreated DIC samples.

Anti-Quorum Sensing and Antioxidant Activity of Essential Oils Extracted From Juniperus Species, Growing Spontaneously in Tebessa Region (East of Algeria)

The chemical composition of essential oils (EOs) extracted from the aerial parts of 2 species of Juniperus was determined by Gas Chromatography-Mass Spectrometry (GC-MS). In total, 65 and 58 compounds accounting for 90.3% and 89.8% of the whole chemical composition of Juniperus oxycedrus (JO) and Juniperus phoenicea (JP) were identified, respectively, with α-pinene, α-amorphene, terpinen-4-ol, α-terpinene, and β-elemene, as major components. For the first time, the capacity to inhibit quorum-sensing for Chromobacterium violaceum CV026 and CV12472 by the investigated EOs was evaluated. Both oils exhibited good violacein inhibition on CV12472 with 100.0 ± 0.0% inhibition at minimal inhibition concentration (MIC) values. Besides, the quorum-sensing inhibition of CV026 was high at MIC for JO essential oil from fruits (JOF, 16.3 ± 2.0 mm), JO leaves (JOL, 12.5 ± 3.5 mm), JP fruits (JPF, 19.7 ± 2.5 mm), and JP leaves (JPL, 21.1 ± 5.0 mm). On both CV12472 and CV026, essential oil from J. phoenicea leaves was the most active inhibitor. All investigated EOs inhibited swarming motilities in flagellated Pseudomonas aeruginosa (PA01) in a concentration-dependent manner, and those from JP were more active than EOs from JO. Moreover, these EOs showed good antioxidant potential according to DPPH● and FRAP methods, especially the EO from JO leaves with an IC50 DPPH● inhibition value of 20.2 ± 1.0 mg/mL. Based on the obtained results, the investigated EOs are good candidates to combat microbial resistance be used as alternatives to conventional antibiotics, and equally find applications in food biosafety as preservatives.

Can hydro-thermo-mechanical treatment by instant controlled pressure-drop (DIC) be used as short time roasting process? Effect of processing parameters on sensory, physical, functional, and color attributes of Egyptian carob powder

This study deals with the manufacture of a specific cocoa-like powder from Egyptian carob. The crucial unit operation consists of texturing/roasting unseeded carob kibbles, with the aim being to ensure perfect control of the chemical transformations that generate the desired flavor, drying to remove excess moisture, deodorizing to eliminate the undesirable flavor, and texturing to favor the physical/micro-mechanical changes that regulate the microstructure of the end product, in order to obtain an expanded-granule powder that can be used in many food formulations. The effect of saturated steam pressure of 0.30-0.60 MPa (133.5-158.8 °C) and processing time of 40-70 s, on the sensory attributes, physical and functional properties, and color characteristics were evaluated and optimized using response surface methodology (RSM). DIC-texturing/roasting could be used to improve the sensory and color characteristics, increase the expansion ratio and oil holding capacity, and decrease the bulk density of DIC-textured/roasted carob powder. The desired quality of textured/roasted carob powder was obtained at 0.60 MPa (158.8 °C) for 55 s (experimental conditions) with water holding capacity close to those of non-textured/unroasted sample. DIC can be used as a coupled process of texturing and roasting at 0.60 MPa for 68 s as predicted by RSM.

Comparative study of the impacts of conventional freezing and dehydrofreezing on apple fruit quality during storage

The present study deals with the impact of storage time on the quality of dehydrofrozen versus conventionally frozen apple. Samples were submitted to freezing as fresh fruit or following the first stage of air drying. The quality was evaluated along a freezing storage period of 18 months under -18 °C. Thaw exudate water (TEW), total colour difference (TCD), and total polyphenol content (TPC) of dehydrofrozen/thawed samples were assessed regarding the water content (W) versus the frozen storage time (FST) (0-18 months). Dehydrofreezing exhibited significant effects on TEW and TCD of dehydrofrozen/thawed apples. Indeed, the lower the W, the lower the TEW content and TCD of partially dried frozen/thawed samples. TPC losses were significant for samples without any pre-dehydration stage and decreased when initial water content decreased. The 18-month frozen storage at -18 °C had the most insignificant effects on all quality response variables for the previously most dried samples. Thus, adequate drying of fruit before freezing is a relevant way to maintain the stability of fruit quality during long-term storage.

Instant Controlled Pressure Drop as Blanching and Texturing Pre-Treatment to Preserve the Antioxidant Compounds of Red Dried Beetroot (Beta vulgaris L.)

Red beetroot is rich in bioactive compounds such as polyphenols, flavonoids, betaxanthins, betacyanins, among others. According to selected processing methods, the bioaccessibility of these compounds could be either enhanced or decreased. This study evaluated the effect of four different drying conditions: (1) Traditional Drying (TD), (2) Swell Drying (SD), (3) DIC Blanching + Traditional Drying (BTD), and (4) DIC Blanching + Swell Drying (BSD) on the antioxidant content and the antioxidant activity of red beetroots. Obtained results showed that in all the cases, by comparing to Traditional Drying (TD), the coupling of a DIC Blanching pre-treatment to a Swell Drying treatment (BSD) maintained or enhanced the preservation of the Total Phenolic Compounds (TPC), the Total Flavonoids Compounds (TFC), the Betanin Concentration (BC), the Trolox Equivalent Antioxidant Capacity (TEAC), and the Free Radical Scavenging Activity by DPPH (IC50) of red beetroots. Various studies have shown that thanks to the expanded and porous structure triggered by the Swell Drying process, it has been possible to achieve better antioxidants extraction and better whole quality. Hence, by coupling DIC as a blanching–steaming pre-treatment, it was possible to preserve better the antioxidant content and the antioxidant activity of red dried beetroots.

Pressure, temperature and processing time in enhancing

Instant Controlled Pressure Drop (DIC) was evaluated as a texturing pre-treatment for the extraction of Camelina sativa (L.) oil. DIC was coupled to Accelerated Solvent Extraction (ASE), Pressing and Dynamic Maceration (DM). DIC optimization was performed by studying the effects of pressure, temperature and processing time on oil yield. DIC + ASE obtained seed-oil yields of 615.9±0.5 against 555.5±0.5 g oil/kg-ddb for untextured seeds (RM). Via pressing, oil yields were 490.9±0.5 and 444.7±0.5 g oil/kg-ddb for textured and untextured seeds, respectively. Through coupling DIC (P: 0.63 MPa and t: 105 s) to the pressing extraction (60 s) of seeds along with 2h of DM of meals, it was possible to reach 605.8 g oil/kg ddb of oil yield. The same results were not obtained for RM seeds, where after 24 h of DM extraction, the oil yield was 554.7 g oil/kg ddb. DIC allowed for an increase in Camelina oil yields, reduced extraction time and valorized pressing meals.

Influence of Instant Controlled Pressure Drop (DIC) on Allergenic Potential of Tree Nuts

Pistachio and cashew contain allergenic proteins, which causes them to be removed from the diet of allergic people. Previous studies have demonstrated that food processing (thermal and non-thermal) can produce structural and/or conformational changes in proteins by altering their allergenic capacity. In this study, the influence of instant controlled pressure drop (DIC) on pistachio and cashew allergenic capacity has been studied. Western blot was carried out using IgG anti-11S and anti-2S and IgE antibodies from sera of patients sensitized to pistachio and cashew. DIC processing causes changes in the electrophoretic pattern, reducing the number and intensity of protein bands, as the pressure and temperature treatment increment, which results in a remarkable decrease in detection of potentially allergenic proteins. The harshest conditions of DIC (7 bar, 120 s) markedly reduce the immunodetection of allergenic proteins, not only by using IgG (anti 11S and anti 2S) but also when IgE sera from sensitized patients were used for Western blots. Such immunodetection is more affected in pistachio than in cashew nuts, but is not completely removed. Therefore, cashew proteins are possibly more resistant than pistachio proteins. According these findings, instant controlled pressure drop (DIC) can be considered a suitable technique in order to obtain hypoallergenic tree nut flour to be used in the food industry.

Apple juice concentrate impregnation enhances nutritional and textural attributes of the instant controlled pressure drop (DIC)-dried carrot chips

BACKGROUND

Osmotic pretreatment is an effective processing unit for improving the textural quality of dried fruit and vegetable snacks, whereas nutrition loss and high calorie after impregnation is still a noteworthy shortcoming of sugar-immersed products. Therefore, the use of apple juice concentrate as a clean label solution to improve the qualities of instant controlled pressure drop (DIC)-dried carrot chips was investigated.

RESULTS

Apple juice concentrate impregnation substantially enhanced the physical properties of the carrot chips, including hardness (38.28 N), crispness (2.01 mm), porosity (66.72%) and homogeneous microstructure, comparable to chips obtained using sucrose and maltiltol based osmotic solutions. Additionally, compared to the sucrose and maltiltol impregnated chips, a higher retention of carotenoids (302.81 μg g^-1 , dry basis), a higher multiplicity of phenolic compounds, stronger antioxidant activities and a superior sensory score were observed in the chips pretreated with apple juice concentrate.

CONCLUSION

Apple juice concentrate could be used as a clean label osmotic solution to enhance the organoleptic attributes and fortify the nutritional properties of DIC-dried carrot snacks. © 2019 Society of Chemical Industry.

Texture and color characteristics of swell-dried ready-to-eat Zaghloul date snacks: Effect of operative parameters of instant controlled pressure drop process

In this work, development of ready-to-eat snacks from Zaghloul date using swell-drying process was studied. Pre-dried Zaghloul date samples having 12% water content on dry basis were textured by instant controlled pressure drop technique (DIC) at different operative parameters, saturated steam pressure (p) and processing time (t), ranged from 0.2 to 0.6 MPa and from 9 to 35 s, respectively. The effect of these operative parameters on texture, color, and sensory characteristics of swell-dried (SD) Zaghloul date snacks were determined and optimized through the response surface methodology. Textural (expansion ratio, hardness, springiness, cohesiveness, and chewiness) and color (L*, a*, b*, C*, and ΔE*) characteristics were significantly affected by the operative parameters of DIC. The optimized textural characteristics was identified for SD Zaghloul date at p = 0.6 MPa and t = 22 s with slight yellowness, while the best color properties were observed for texturing conditions of p = 0.2 MPa and t = 22 s. The expansion ratio ε_r was then 46% higher and the hardness was 262% lower for SD than airflow-dried date. Instrumental analysis such as texture profile analysis and Hunter's Lab color analyzer could be used to describe the texture and color changes occurred during food drying. Beside these analyses, the expansion ratio could be used to describe the texture as well. Swell-drying process, an alternative drying process, is defined as DIC-assisted hot air drying. The thermo-mechanical effects of DIC are mainly induced by the abrupt pressure drop toward a vacuum after short-time treatment (9-35 s) by saturated steam pressure (0.2 up to 0.6 MPa). The abrupt pressure drop rate induces an autovaporization of product's water immediately decreasing the product's temperature allowing it to cross the glass transition Tg border. The impact of DIC operative parameters on Zaghloul date could be observed through the expansion ratio, and the textural characteristics (hardness HA, springiness SP, cohesiveness CO, and chewiness CH).

Optimization of the Spray Drying Operating Conditions for Producing the Powder Mixture of Gum Arabic and Maltodextrin

The powder mixture of gum arabic and maltodextrin was produced by spray drying. The inlet air temperature of spray dryer was varied from 160 °C to 260 °C and the maltodextrin content was varied from 0 to 50 % in the feed solution with the concentration of 42.5 % (w/v) total solids by weight. The properties of the finished product were characterized to examine the impact of changes in these operating parameters. The results showed that: the inlet air temperature had a stronger influence on the properties of finished product than the MD/GA ratio, whereas the feed rate was more clearly affected by the MD/GA ratio. Two optimal parameters obtained include MD/GA ratio equal to 0.615 and the inlet air temperature of spray dryer Te = 258 °C.

Treatment of Lupin Seed Using the Instantaneous Controlled Pressure Drop Technology to Reduce Alkaloid Content

Despite their high protein content, lupin seeds are not as fully utilised as some other grain legumes. The drawback in their utilisation is mainly due to the presence of water soluble, poisonous alkaloids. In this study, an instantaneous controlled pressure drop (DIC) treatment followed by an aqueous extraction was performed on lupin seeds. Two species Lupinus albus and Lupinus mutabilis with different initial total alkaloid content of 0.025% and 5.5% (d.b.), respectively have been studied. Lupanine was the major alkaloid found in both lupin species. Experimental results proved the feasibility of using DIC treatment to reduce the alkaloid content of lupin seeds. Optimised DIC treatment combined with an adequate 2h soaking in water reduced the alkaloid content from 5.5% to 2.2% of L. mutabilis and from 0.025% to 0.0075% of L. albus.

Comparative Study of the Effects of Drying Methods on Antioxidant Activity of Dried Strawberry (Fragaria Var. Camarosa)

<p>Hot air drying (HAD), freeze-drying (FD), and swell-drying (SD, coupling instant controlled pressure drop, DIC, to standard hot air) were applied to strawberries (<em>Fragaria</em> var. Camarosa). The total phenol, total flavonoid, and total anthocyanin contentswere evaluated versusthe drying methods. The correlations between the bioactive compounds and antioxidant activity were investigated. The obtained results showed that the differences in phenol levels were no quite comparing the three drying techniques; however, great variations were reported for anthocyanin and flavonoid content.</p> A strong correlation between the antioxidant activity and anthocyanin content was found in SD strawberries. Also, it was observed that saturated steam pressure (P) of DIC texturing operation, had a significant effect on the studied parameters compared to the thermal holding time (t). The optimum conditions of DIC were P = 0.35 MPa for t = 10 s to obtain the highest levels of phenols, flavonoids, and anthocyanins, as well as antioxidant activity.

Yield and Composition of Indonesian Cananga Oil Obtained by Steam Distillation and Organic Solvent Extraction

Cananga oil has high economical value because of its utilisation as fragrance and food flavour. In the present work, the oil was isolated by steam distillation and organic solvent extraction from dry mature flowers of Cananga odorata Hook. fil. et Thomson, forma macrophylla. Chloroform and hexane were used as solvents with different polarities. The yield of volatile oil and its grouped compounds (LOC, sesquiterpenes hydrocarbons and HOC) was investigated as a function of time. LOC consists of oxygenated monoterpenes and other light oxygenated compounds whereas HOC comprises oxygenated sesquiterpenes and other heavy oxygenated compounds. The oil yields of 5.1, 3.8 and 2.5 % dry matter were obtained with chloroform (8 h), hexane (8 h) and steam distillation (16 h), respectively. The isolation rate was described by a first-order kinetics equation. The rate was lowest with steam distillation, intermediate with hexane extraction and best with chloroform extraction. The oil composition was analyzed by gas chromatography coupled to mass spectrometry. The steam-distilled oil and chloroform oil had a similar composition, with a high content of oxygenated compounds (61.7% and 58.3%), while hexane oil was rich in sesquiterpenes hydrocarbons (66.5%).

Effect of instant controlled pressure drop on IgE antibody reactivity to peanut, lentil, chickpea and soybean proteins

BACKGROUND

The use of legume seeds is being expanded in the food industry due to their excellent nutritional and technological properties. However, legumes have been considered causative agents of allergic reactions through ingestion. Previous studies indicated that processing methods combining heat and steam pressure, such as instant controlled pressure drop (DIC®), could decrease allergenicity. The aim of this study was to investigate the impact of DIC treatment on peanut, lentil, chickpea and soybean IgE antibody reactivity.

METHODS

Peanut, lentil, chickpea and soybean seeds were subjected to DIC treatment at different pressure and time conditions (3 and 6 bar for 1 and 3 min). Control (raw) and DIC-treated extracts were analyzed by SDS-PAGE and immunoblotting using a serum pool from sensitized patients.

RESULTS

DIC treatment did not affect the total protein content of legume seeds. Nevertheless, modifications of protein profiles after DIC showed a general decrease in IgE binding to legume proteins that was correlated to a higher steam pressure and longer treatment. The immunoreactivity of soybean proteins was almost abolished with treatment at 6 bar for 3 min.

CONCLUSIONS

The results demonstrated that DIC treatment produces a reduction in the overall in vitro IgE binding of peanut, lentil and chickpea and a drastic reduction in soybean immunoreactivity.

Effect of an Instantaneous Controlled Pressure Drop on in vitro Allergenicity to Lupins (Lupinus albus var Multolupa)

BACKGROUND

Lupin seed flour has been reported as a causative agent of allergic reactions, especially in patients with allergy to peanut. Previous studies have demonstrated that autoclave treatment can considerably reduce the allergenicity of lupins.

AIMS

The aim of this work was to evaluate the effect of instantaneous controlled pressure drop (détente instantanée contrôlée, DIC) treatment on lupin in vitro allergenicity.

METHODS

Lupin cotyledons were subjected to instantaneous controlled pressure drop at several pressure and time conditions (3, 4.5 and 6 bar for 1, 2 and 3 min, respectively). Immunoreactivity to raw and DIC-treated extracts was evaluated by Western blot using a serum pool from 19 sensitized patients.

RESULTS

Depending on the operating parameters used during DIC treatment, a reduction in protein solubility of lupin seed was observed. Moreover, drastic modifications in protein profiles were observed after DIC treatment by SDS-PAGE analysis. Western blot experiments showed that the decreases in IgE binding to lupin proteins were associated with the increases in steam pressure and time treatment, and binding was completely abolished by DIC at 6 bar for 3 min.

CONCLUSIONS

The results suggest that DIC treatment could produce a reduction in lupin allergenicity.