Headspace Volatiles and Physical Characteristics of Vacuum-microwave, Air, and Freeze-dried Oregano (Lippia berlandieri Schauer)

Nutraceutical Difference between Two Popular Thai Namwa Cultivars Used for Sun Dried Banana Products

Musa (ABB group) “Kluai Namwa” bananas (Musa sp.) are widely grown throughout Thailand. Mali Ong is the most popular Kluai Namwa variety used as raw material for sun-dried banana production, especially in the Bangkratum District, Phitsanulok, Thailand. The sun-dried banana product made from Nanwa Mali Ong is well recognized as the best dried banana product of the country, with optimal taste compared to one made from other Kluai Namwa varieties. However, the production of Mali Ong has fluctuated substantially in recent years, leading to shortages. Consequently, farmers have turned to using other Kluai Namwa varieties including Nuanchan. This study investigated the nutraceutical contents of two popular Namwa varieties, Mali Ong and Nuanchan, at different ripening stages. Nutraceuticals in the dried banana products made from these two Kluai Namwa varieties and four commercial dried banana products were compared. Results indicated that the content of moisture, total sugar, and total soluble solids (TSS) (°Brix) increased, while total solids and texture values decreased during the ripening stage for both Kluai Namwa varieties. Rutin was the major flavonoid found in both Namwa Mali Ong and Nuanchan varieties ranging 136.00−204.89 mg/kg and 129.15−260.38 mg/kg, respectively. Rutin, naringenin, quercetin and catechin were abundant in both Namwa varieties. All flavonoids increased with ripening except for rutin, gallocatechin and gallocatechin gallate. There were no significant differences (p < 0.05) in flavonoid contents between both varieties. Tannic acid, ellagic acid, gallic acid, chlorogenic acid and ferulic acid were the main phenolic acids found in Mali Ong and Nuanchan varieties, ranging from 274.61−339.56 mg/kg and 293.13−372.66 mg/kg, respectively. Phenolic contents of both varieties decreased, increased and then decreased again during the development stage. Dopamine contents increased from 79.26 to 111.77 mg/kg and 60.38 to 125.07 mg/kg for Mali Ong and Nuanchan, respectively, but the amounts were not significantly different (p < 0.5) between the two Namwa varieties at each ripening stage. Inulin as fructooligosaccharide (FOS) increased with ripening steps. Production stages of sun-dried banana products showed no statistically significant differences (p < 0.05) between the two Namwa varieties. Therefore, when one variety is scarce, the other could be used as a replacement in terms of total flavonoids, phenolic acid, dopamine and FOS. In both Namwa varieties, sugar contents decreased after the drying process. Sugar contents of the dried products were 48.47 and 47.21 g/100 g. The drying process caused a reduction in total flavonoid contents and phenolic acid at 63−66% and 64−70%, respectively. No significant differences (p < 0.05) were found for total flavonoid and phenolic contents between the dried banana products made from the two Namwa varieties (178.21 vs. 182.53 mg/kg and 96.06 vs. 102.19 mg/kg, respectively). Products made from Nuanchan varieties (24.52 mg/kg) contained significantly higher dopamine than that from Mali Ong (38.52 mg/kg). The data also suggest that the banana maturity stage for production of the sun dried products was also optimum in terms of high nutraceutical level.

Effects of Different Pre-drying and Drying Methods on Volatile Compounds in the Pericarp and Kernel of Amomum tsao-ko

The effects of twelve different pre-drying and drying methods on the chemical composition in the pericarp and kernel of Amomum tsao-ko were studied. The volatile components were isolated from the samples by simultaneous distillation and extraction and analyzed by gas chromatography-mass spectrometry (GC-MS). Sixty and thirty-eight compounds were identified from pericarp and kernel, respectively, and the main constituents were oxygenated monoterpenes. These compounds were not only significantly affected by pre-drying and drying methods but also varied in content due to different tissue locations. The total volatile content of pericarp varied from 0.70 to 1.55%, with the highest obtained by microwave-dried samples (150 W) and the lowest in freeze-dried samples. The total volatile content of the kernel varied from 6.11 to 10.69%, with the highest content obtained during sun drying (SD) and the lowest content in samples treated with boiling water for 2 min. Oxygenated monoterpenes were the highest compounds in pericarp and kernel, which were also the most affected by drying methods. The highest content of oxygenated monoterpenes in the pericarp (0.77%) could be obtained by boiling water treatment for 5 min, and the highest content of oxygenated monoterpenes in the kernel (7.48%) could be obtained by SD. Additionally, the main components such as 1,8-cineole, 2-carene, (Z)-citral, nerolidol, (Z)-2-decenal, (E)-2-dodecenal, citral, (E)-2-octenal, 4-propylbenzaldehyde, and phthalan showed remarkable variations in pre-drying and drying methods.

Vacuum microwave dehydration decreases volatile concentration and soluble protein content of pea (Pisum sativum L.) protein

BACKGROUND

Peas are an inexpensive yet nutritious and sustainable source of protein. However, it is challenging to incorporate pea proteins into food formulations owing to their beany or green off-flavours and their limited water solubility.

RESULTS

Vacuum microwave dehydration (VMD) of pea protein with an initial moisture content of 425% (dry basis, db) at 2 W g-1 specific microwave energy and 200 Torr vacuum level for 88 min led to an 83% reduction in total volatile compound concentration. VMD processing at high initial moisture contents facilitated the Maillard reaction, enhancing the extent of protein cross-linking, leading to a marked decrease in soluble protein content, to 11 g kg-1 . Reducing the initial moisture content to 56% db greatly retained protein solubility (112-113 g kg-1 ), but it only led to a minor reduction in total volatile compound concentration (2-11% reduction). A high microwave energy (20 W g-1 )-short time (2 min) treatment at 200 Torr vacuum level was found optimal, reducing both volatile levels and soluble protein content by ~50%.

CONCLUSION

Evidently, it is difficult to employ VMD without reduction of pea protein solubility and corresponding changing in functionality. Yet, if optimized, VMD has the capability to decrease volatile concentrations while retaining protein solubility. Future sensory analysis should be conducted to determine whether the aforementioned reductions in total volatile compound concentration may have a notable effect on consumer palatability. © 2020 Society of Chemical Industry.

A review of drying methods for improving the quality of dried herbs

A large number of herb-drying studies have been conducted in recent decades and several herb-drying techniques have been introduced. However, the quality of commercial dried herbs is still lower than that of fresh herbs. In this paper, studies regarding the effect of drying techniques and pre-drying treatments on the aroma and color of dried herbs are reviewed with the aim of providing an overview of different technological strategies developed for improving the quality of aromatic herbs for their industrial drying.

Fortification of condiments with micronutrients in public health: from proof of concept to scaling up

Fortification of condiments or seasonings may be useful for delivering micronutrients if they are consumed consistently by most of the population, as occurs in many countries. The World Health Organization, in collaboration with the Micronutrient Initiative and the Sackler Institute for Nutrition Science at the New York Academy of Sciences, convened a technical consultation on "Fortification of Condiments and Seasonings with Vitamins and Minerals in Public Health: from Proof of Concept to Scaling Up" to review the role of condiments and seasonings in improving micronutrient status, as constituents of regular diets and patterns of production and consumption worldwide. The consultation covered aspects related to implementation, monitoring, evaluation, and legal frameworks of fortification programs, as well as food safety and policy coherence for condiment fortification in the context of other public health strategies. This paper introduces the background and rationale of the technical consultation, synopsizes the presentations, and provides a summary of the main considerations proposed by the working groups.

Chemical composition, potential toxicity, and quality control procedures of the crude drug of Cyrtopodium macrobulbon

ETHNOPHARMACOLOGICAL RELEVANCE

Cyrtopodium macrobulbon ("cañaveral") has been long used in Mexican traditional medicine for the treatment of painful urinary ailments ("mal de orin") in men. This study was conducted (i) to establish the potential acute toxicity and the antinociceptive activity of some preparations of Cyrtopodium macrobulbon, in order to demonstrate its preclinical efficacy for treating symptoms of "mal de orin"; and (ii) to determine the chemical composition and quality control parameters of this medicinal orchid.

MATERIALS AND METHODS

The antinociceptive effect was assessed using the acetic acid-induced writhing and the hot-plate tests. Investigation of the acute toxicity was accomplished by the Lorke method. The organic extract (OE) was subjected to conventional phytochemical study using chromatographic conventional procedures. The volatile components profile of the species was accomplished via GC-MS analysis of HS-SPME-adsorbed compounds. Furthermore, an HPLC method to quantify ephemeranthol B (10) was developed and validated according to the International Conference on Harmonization Guidelines. Microscopic anatomy studies were performed using light and scanning electron microscopies. Finally, a potential distribution map was generated using the MaxEnt modeling method.

RESULTS

AE and OE were not toxic to mice since the LD50 was higher than 5000 mg/kg. OE was only active in the acetic acid-induced writhing assay at the doses of 100 and 316 mg/kg. Conventional phytochemical analysis of OE led to the isolation and characterization of n-hexacosyl-trans-p-coumarate (1), n-octacosyl-trans-p-coumarate (2), n-triacontyl-trans-p-coumarate (3), 4-methoxy-benzyl alcohol (4), 4-hydroxybenzaldehyde (5), 1,5,7-trimethoxy-9,10-dihydrophenanthrene-2,6-diol (6), confusarin (7), gigantol (8), batatasin III (9), and ephemeranthol B (10). The major volatile components identified by HS-SPME analysis were 6,10,14-trimethyl-2-pentadecanone, eucalyptol (11), and isobornyl formate. An HPLC analytical method for the quantification of compound 10 in the plant was developed and fully validated for selectivity, accuracy, and precision. The microscopic studies revealed that the epidermal tissue displayed a layer of enlarged, crenate and cell thin-walled cells with a thickened cuticle; these cells are described for first time for this species. The potential distribution map generated revealed that this species is widespread in Mexico from Sinaloa to Merida states.

CONCLUSIONS

The results of the pharmacological studies tend to support the traditional use of Cyrtopodium macrobulbon for "mal de orin"; the presence of compounds 8, 9, and 11 with known antinociceptive activity might be related with the pharmacological effect demonstrated. The HPLC and microscopic analyses developed in this work will be valuable tools for quality control purposes for this plant.

Evaluation of drying process on the composition of black pepper ethanolic extract by high performance liquid chromatography with diode array detector

BACKGROUND

Black pepper (Piper nigrum) is one of the well-known spices extensively used worldwide especially in India, and Southeast Asia. The presence of alkaloids in the pepper, namely, piperine and its three stereoisomers, isopiperine, chavicine and isochavicine are well noticed.

OBJECTIVES

The current study evaluated the effect of lyophilization and oven drying on the stability and decomposition of constituents of black pepper ethanolic extract.

MATERIALS AND METHODS

In the current study ethanolic extract of black pepper obtained by maceration method was dried using two methods. The effect of freeze and oven drying on the chemical composition of the extract especially piperine and its three isomers were evaluated by HPLC analysis of the ethanolic extract before and after drying processes using diode array detector. The UV Vis spectra of the peaks at piperine retention time before and after each drying methods indicated maximum absorbance at 341.2 nm corresponding to standard piperine.

RESULTS

The results indicated a decrease in intensity of the chromatogram peaks at approximately all retention times after freeze drying, indicating a few percent loss of piperine and its isomers upon lyophilization. Two impurity peaks were completely removed from the extract.

CONCLUSIONS

In oven dried samples two of the piperine stereoisomers were completely removed from the extract and the intensity of piperine peak was increased.

Chemical composition and antimicrobial and spasmolytic properties of Poliomintha longiflora and Lippia graveolens essential oils

In the present study, we reported a comparative analysis of the chemical composition and pharmacological properties of the essential oils obtained from 2 Mexican oreganos, Poliomintha longiflora and Lippia graveolens. The gas chromatography-mass spectrometry (GC-MS) profiles of the oils showed high amounts of oxygenated monoterpenes, mainly carvacrol (%[mg/100 g dry matter]) (18.36 [459.0] in P. longiflora and 13.48 [164.7] in L. graveolens). In addition, these oils contained marked quantities of p-cymene (14.09 [352.2] and 7.46 [37.3], respectively), β-caryophyllene oxide, β-caryophyllene, and carvacrol acetate. Headspace analyses of the leaves of both species using different coated fibers revealed that γ-terpinene, eucalyptol, and p-cymene were the principal light volatile components. Chromatographic fingerprints and a suitable analytical method for quantifying the main components of both essences were established using high-performance liquid chromatography (HPLC) as analytical tool. The essential oils of both species were not toxic in the acute toxicity studies in mice performed according to the Lorke procedure (DL(50) > 5000 mg/kg). The oils and the major constituents, carvacrol and p-cymene, displayed a moderate in vitro antibacterial activity, with minimum inhibitory concentration values ranging from 128 to 512 μg/mL. In addition, these samples demonstrated a marginal antispasmodic activity in vivo and provoked a concentration-dependent inhibition of the carbachol- and histamine-induced contractions using the isolated guinea-pig ileum preparation. In particular, p-cymene exerts good selective inhibitory activity on the carbachol-induced contractions (IC(50) = 9.85 μg/mL).

PRACTICAL APPLICATION

The analytical methods using GC-MS and HPLC techniques will be useful for establishing quality control as well as preclinical pharmacological and toxicological parameters of the crude drug P. longiflora, which is widely used as substitute of L. graveolens for medicinal and flavorings purposes. This overall information will be also useful for elaborating scientific and pharmacopoeic monographs of this very Mexican medicinal plant.

Intermittent Microwave-convective Air Drying of Oregano

Effectiveness of intermittent microwave-convective air drying (IMWC) was investigated and compared to continuous microwave-convective air drying (CMWC) and convective air drying for oregano. Both CMWC and IMWC increased the drying rate of oregano compared to convective drying. The CMWC and IMWC were 12.7-14.0 and 4.7-11.2 times more energy efficient in drying than convective drying, respectively. The highest essential oil contents were obtained from convective drying at 40 °C and 45 °C. However, these treatments had the longest drying time and the highest energy consumption. The CMWC yielded the lowest essential oil content and resulted in an extreme change in the essential oil composition. The IMWC, except with the pulse ratio of 3.0, resulted in similar essential oil content compared to convective drying at 50 °C and shade drying. No identical result was found among the prevailing compounds of essential oil of oregano obtained from shade drying, convective drying and IMWC. Both CMWC and IMWC did not yield acceptable results of product color. However, in terms of essential oil content and quality, the IMWC at 25 °C room temperature with the pulse ratio of 5.0 was judged as the most suitable drying method for oregano due to its rational drying time and energy consumption compared to CMWC drying, convective air dying, and shade drying.

The effect of freeze-drying and its implications for botanical medicine: a review

Botanical samples are often freeze-dried (lyophilized) for use in research studies, and a variety of freeze-dried botanicals are marketed to the public. In both instances, there is an underlying assumption that freeze-drying properly preserves the medicinal qualities of plants, and is superior to other preservation methods. In fact, little systematic research has been done to verify this assumption. A review of the existing research, done primarily by the food and spice industry, indicates that freeze-drying has unanticipated and significant effects on the constituent profiles of medicinal plants that puts into question whether freeze-drying necessarily is the best method to preserve botanical medicines.This research review finds there is insufficient information to conclude that freeze-drying has negative effects on the medicinal qualities of plants. But, because existing research indicates that freeze-drying imperfectly preserves important classes of medicinal compounds (such as volatiles, phenolics and carotenoids), may increase the mutation rate in unicellular organisms and may diminish some medicinal plant actions, researchers and practitioners should carefully consider how the use of freeze-dried material may affect pharmacological and clinical study results.

Influence of drying on the flavor quality of spearmint (Mentha spicata L.)

Spearmint (Mentha spicata L.) was dried using three different drying methods: oven-drying at 45 degrees C, air-drying at ambient temperature, and freeze-drying. The effect of the drying method on the volatile compounds and on the structural integrity and sensory characteristics of the spice was evaluated. The volatile components from fresh and dried spearmint samples were isolated by simultaneous distillation-extraction (SDE) and analyzed by gas chromatography-mass spectrometry (GC-MS). A total of 28 compounds were identified, carvone, limonene, and 1,8-cineole, in that order, being the main components in all of the samples. Oven-drying at 45 degrees C and air-drying at ambient temperature were the methods that produced the best results. An increase in monoterpenes was observed in all of the dried samples, except in the freeze-dried samples that underwent freezing at -198 degrees C. Freeze-drying resulted in substantial losses in oxygenated terpenes and sesquiterpenes. The effect of each drying method on leaf structure was observed by scanning electron microscopy. From a sensory standpoint, drying the spearmint brought about a decrease in herbaceous and floral notes together with an increase in minty odor.

Characterization of Citrus unshiu (C. unshiu Marcov. forma Miyagawa-wase) blossom aroma by solid-phase microextraction in conjunction with an electronic nose

The volatile composition of the headspace from Citrus unshiu Marcov. forma Miyagawa-wase blossom was investigated. The volatile constituents were absorbed by a solid-phase microextraction (SPME) fiber and directly transferred to a GC-MS. Volatile compositional changes of C. unshiu blossom prepared via different drying methods (shade, microwave, and freeze-drying methods) were also determined. A total of 96 volatile constituents were confirmed in the headspace from these samples. Monoterpene hydrocarbons were prominent in the headspace volatiles of C. unshiu blossom: fresh, 84.1%; shade-dried, 60.0%; microwave-dried, 88.4%; and freeze-dried, 29.9%. p-Cymene (23.3%) was the most abundant component in the headspace of fresh C. unshiu blossom; gamma-terpinene was the most abundant in shade- and microwave-dried samples (26.8 and 31.2%, respectively) and beta-caryophyllene (10.5%) in freeze-dried sample. By using an electronic nose consisting of six metal oxide sensors, principal component analysis of the volatile compounds showed a clear aroma discrimination of the fresh and all dried blossom samples.

Flavor and texture of banana chips dried by combinations of hot air, vacuum, and microwave processing

The behavior of 16 volatile compounds of banana during a combination of air-drying (AD) and vacuum microwave-drying (VMD) of banana chips was characterized. Samples were AD to remove 60, 70, 80, or 90% of moisture (wet basis) and then subjected to VMD to achieve a final moisture content of 3% (dry basis). Banana slices were also dehydrated using only AD, VMD, and freeze-drying (FD) for comparison. Samples that underwent more VMD had significantly lower levels of volatile compounds, which is attributed to the decreased formation of an impermeable solute layer on the surface of the chips. High values for water solubility and relative volatility of compounds correlated with losses during VMD; however, additional factors appear to influence the behavior of compounds during VMD processing. The optimal process of 90%AD/10%VMD yielded crisper banana chips with significantly higher volatile levels and sensory ratings than AD chips.