Pepper Berries Research Articles

Effect of harvesting stage on postharvest quality of black pepper piper nigrum l. cultivars grown in Morogoro, Tanzania

Optimal harvest maturity stage determines the on-shelf quality of black pepper (Piper nigrum L.). Small-scale farmers in Morogoro harvest black pepper before reaching full maturity to catch up with high market prices offered early in the season. Unfortunately, traders are complaining on the quality of black pepper from the area. This study evaluated the effect of harvesting stages on post-harvest quality of pepper cultivars grown in the Morogoro district. Pepper cultivars; Babu kati, Babu kubwa, and Ismailia at premature and mature stages were dried on coconut leaves mats to suitable drying stage. Treatments in a 2 x 3 factorial experiment following a complete randomized design (CRD) were replicated thrice. Statistical significance of variables was generated by ANOVA and mean separation by Tukey HSD test at p ≤ 0.05. Results showed a significant (p<0.001) difference between harvest stages and cultivars on berry colour, moisture content, berry firmness, dry recover and weight loss percentage. Pepper berries at pre-mature stage across cultivars had higher (79.11%) initial moisture content than mature berries (71.6%). Mature berries had higher dry recovery percentage (28.84%) than pre mature (15.78%). Mature “Ismailia” berries had the highest firmness (10.5kg/mm2) than premature (5.8 kg/mm2). During sun drying, colour values L*(brightness), and b* (yellowness) decreased significantly while greenness decreased as a* values increased from more negative values to zero in both harvesting stages as pepper berries darkened. Colour changes were sharper on mature than pre-mature harvested pepper corns. These findings will help farmers to make right decision on when to harvest for quality black pepper product. Farmers are recommended to harvest black pepper when mature for better firmness and colour development during drying. Further studies are required to determine the sensory quality and volatile oil contents of the cultivars when harvested premature and mature stages.

Correlation Studies and Kinetic Modelling of Electrocoagulation Treatment of Pepper Wastewater

Pepper processing is one of the largest productions that significantly contribute (98%) to Sarawak, Malaysia’s economic and agricultural sectors. The prolonged retting process of pepper berries would cause undesirable dark colour and acidic wastewater. This study aims to evaluate the performance of an electrocoagulation treatment using nickel and copper electrodes for the changes in turbidity and pH of pepper wastewater. Some analyses (correlation studies and kinetic modelling) were studied. The electrocoagulation treatment was conducted by having two conditions nickel and copper electrodes immersed in 400 mL of pepper wastewater for 30 minutes. Every 5 minutes, it was monitored, and the sample was taken for further analysis. The results indicated a significant decrease in the turbidity of pepper wastewater for nickel (98.25%) and copper electrodes (86.32%) was noticed with the increase in the electrocoagulation treatment time. At the same time, the pH values for nickel and copper electrodes were increased by 27.43% and 31%, respectively. The results were evaluated by using Principal Component Analysis (PCA). PCA describes the correlation between the wastewater qualities in this study within less time. Among four models (zero, first and second-order) applied in this study, the turbidity for nickel and copper electrodes had the highest R2 values (0.9457 and 0.9899) in the zero-order model. For pH, the second-order model had the highest R2 values (0.9508 and 0.9657) for nickel and copper electrodes. Electrocoagulation using nickel and process electrodes is a practical method to treat pepper wastewater.

Durian Waste Husks as an Adsorbent in Improving Soaking Water during the Retting Process of Piper nigrum L. (Pepper Berries)

The potential of raw durian husk and NaOH-modified durian husk as an adsorbent, using different doses, 0.5 g, 1.0 g, 1.5 g, and 2.0 g, is investigated to improve soaking water of pepper berries during the retting process. The surface area and the pore size of the durian husk were examined using Brunner Emmett and Teller analysis. The surface area of NaOH-modified durian husk is higher (2.33 m2/g) compared to the raw durian husk (1.51 m2/g). NaOH-modified durian husk has a higher porous structure than the raw durian husk, but both pore diameters are more than 50 nm, which is considered micropore raw material. The effect of the raw durian husk on pH, chemical oxygen demand (COD), dissolved oxygen (DO), and turbidity were compared to the NaOH-modified durian husk with different doses. The 2.0 g of NaOH-modified durian husk enhanced changes in the four parameters. The highest pH value using NaOH-modified durian husk was 6.10 ± 0.02, while turbidity and COD increased to 971.33 ± 1.15 NTU and 1984.67 ± 3.21 mg/L, respectively. The DO of NaOH-modified durian husk shows the lowest reduction to 1.49 mg/L with 2.0 g of NaOH-modified durian husk. The experimental data was best fitted with a first-order kinetic model. Durian husk treated with NaOH could be used as a potential adsorbent to enhance the soaking water for pepper berries.

Antioxidant, Alpha-Glucosidase Inhibition Activities, In Silico Molecular Docking and Pharmacokinetics Study of Phenolic Compounds from Native Australian Fruits and Spices.

Native Australian fruits and spices are enriched with beneficial phytochemicals, especially phenolic compounds, which are not fully elucidated. Therefore, this study aimed to analyze native Australian mountain-pepper berries (Tasmannia lanceolata), rosella (Hibiscus sabdariffa), lemon aspen (Acronychia acidula), and strawberry gum (Eucalyptus olida) for phenolic and non-phenolic metabolites and their antioxidant and alpha-glucosidase inhibition activities. Liquid chromatography-mass spectrometry-electrospray ionization coupled with quadrupole time of flight (LC-ESI-QTOF-MS/MS) was applied to elucidate the composition, identities, and quantities of bioactive phenolic metabolites in Australian native commercial fruits and spices. This study identified 143 phenolic compounds, including 31 phenolic acids, 70 flavonoids, 10 isoflavonoids, 7 tannins, 3 stilbenes, 7 lignans, 10 other compounds, and 5 limonoids. Strawberry gum was found to have the highest total phenolic content (TPC-36.57 ± 1.34 milligram gallic acid equivalent per gram (mg GAE/g), whereas lemon aspen contained the least TPC (4.40 ± 0.38 mg GAE/g). Moreover, strawberry gum and mountain pepper berries were found to have the highest antioxidant and anti-diabetic potential. In silico molecular docking and pharmacokinetics screening were also conducted to predict the potential of the most abundant phenolic compounds in these selected plants. A positive correlation was observed between phenolic contents and biological activities. This study will encourage further research to identify the nutraceutical and phytopharmaceutical potential of these native Australian fruits.

Modeling for thin layer drying of black pepper (Piper nigrum) in a reverse air flow dryer

AbstractDrying of freshly harvested green pepper (Piper nigrum) was performed in a reverse air flow mechanical dryer (RRLT‐NC – 101). Fresh and blanched pepper of varieties, Sreekara and Panniyur‐1 were dried at 50°C, 55°C, and 60°C. Blanching was done by dipping in boiling water for 1 min. The experimental data for moisture loss was converted to moisture ratios and fitted to five thin layer drying models to describe the drying process mathematically. The results were compared for their goodness of fit in terms of coefficient of determination (r2), root mean square error (RMSE) and mean square of deviation (χ2). Logarithmic model was found most suitable to describe the drying process of black pepper. The unblanched Sreekara took 42, 34, and 26 h and blanched took 36, 30, and 24 h to dry from moisture content of 180.89–9.4% d.b. at air temperatures of 50°C, 55°C, and 60°C, respectively. In case of Panniyur the unblanched took 44, 36, and 28 h and blanched took 37, 32, and 26 h to dry from moisture content of 197.62–9.2% d.b. for the same temperatures. The effective moisture diffusivity varied from 3.28 × 10−7 to 6.44 × 10−7 m2/s. The activation energy was higher for unblanched than for blanched black pepper varied between 39.45 and 44.05 kJ/mol.Practical applicationsDrying of harvested pepper is one of the most important unit operations during processing of green pepper. Sun drying is the conventional method followed for drying. The despiked pepper berries are dried under sun for 4–5 days to bring the moisture content below 11%. The process of blanching green pepper in boiling water for 1 min followed by mechanical drying could produce better quality dried product. A simple reverse air flow, natural convection mechanical dryer suitable for drying various agricultural produce at farm level was used for drying green pepper. The results of the study could be applied for gathering information related to the drying process in a mechanical dryer like the drying kinetics, effective moisture diffusivity and activation energy as well as the effect of blanching on these parameters.

Ripening-Induced Changes in the Nutraceutical Compounds of Differently Coloured Pepper (Capsicum annuum L.) Breeding Lines.

To date, several research studies addressed the topic of phytochemical analysis of the different coloured pepper berries during ripening, but none discussed it in the case of purple peppers. In this study we examine whether the anthocyanin accumulation of the berries in the early stages of ripening could result in a higher antioxidant capacity due to the elevated amount of polyphenolic compounds. Therefore, enzymatic and non-enzymatic antioxidant capacity was measured in four distinct phenophases of fruit maturity. Furthermore, the expression of structural and regulatory genes of the anthocyanin biosynthetic pathway was also investigated. An overall decreasing trend was observed in the polyphenolic and flavonoid content and antioxidant capacity of the samples towards biological ripeness. Significant changes both in between the genotypes and in between the phenophases were scored, with the genotype being the most affecting factor on the phytonutrients. An extreme purple pepper yielded outstanding results compared to the other genotypes, with its polyphenolic and flavonoid content as well as its antioxidant capacity being the highest in every phenophase studied. Based on our results, besides MYBa (Ca10g11650) two other putative MYBs participate in the regulation of the anthocyanin biosynthetic pathway.

Development of inductively coupled plasma-mass spectrometry method for determination of trace metals in black pepper berries

Development of inductively coupled plasma-mass spectrometry method for determination of trace metals in black pepper berries

Effects of flowing water on soaking water quality during the retting process of pepper berries (Piper nigrum L.)

This study assesses the effects of flowing water on soaking water quality during the retting process of pepper berries. Generally, there are organic matters and the bioactive compounds that naturally exist in pepper that may have leached out into the soaking water because of the prolonged retting process. Daily samplings were carried out by triplicate of water sample for 7 consecutive days. The soaking test was carried out by having 5 kg of pepper berries soaked under the flowing water with the flow rate 70 L/min. Six parameters were measured based on standard methods: pH, turbidity, dissolved oxygen, chemical oxygen demand total dissolved solids and colour. The results showed the changes of soaking water in turbidity (from 13.73 ±0.85 NTU to 33.53 ±0.71 NTU), pH (from 6.95 ±0.02 to 6.23), dissolved oxygen (from 7.75 ±0.09 g/ml to 6.15 ±0.02 g/ml), chemical oxygen demand (from 24.33 ±1.53 g/ml to 27.67 ±1.53 g/ml), total dissolved solid (from 39.53 ±2.36 g/ml to 58.50 ±0.65 g/ml) and total colour change (from 0.53 ±0.09 to 0.87 ±0.03) during the retting process were corresponding to the soaking time. As a result, this study reveals that the use of flow water for the retting process has a higher tendency to avoid sedimentation and, in the meantime, to ensure the quality of the white pepper.

Quality Improvement of White Pepper with Processing through Optimizing the Ratio of Starter Culture from Acetobacter sp., Bacillus subtilis, and Bacillus cereus

Fermentation process using known microbial species can be exploited for the processing of white pepper. It is expected to generate quality of white pepper in a short period soaking time. This research aimed to study characteristics of white pepper through a fermentation process by addition of combination isolates of Acetobacter sp., B. subtilis, and B. cereus. After threshing, 2 kg of fresh pepper berries was soaked in water mixed with starter culture. The experiment used a completely randomized design, two replications. The treatment consisted of: A) starter culture ratio of Acetobacter sp.: B. subtillis: B. cereus (A1 = 0:0:0; A2 = 1:1:1; A3 = 2:1:1; A4 = 1:2:1; and A5 = 1:1:2) and soaking time (B1 = 5 and B2 = 7 days). Fermented pepper was decorticated, washed, and dried. The best treatment was fermented for 7 days with the combination isolates of Acetobacter sp., B. subtilis, and B. cereus with ratio 2:1:1. This condition produced white pepper in fulfilling in requirement of SNI standards with piperine and essential oil contents and TPC of 5.95%, 2.95% and 1.1 x 102 CFU/g, respectively. This process is expected to generate high quality of white pepper in a short soaking time.

Production, Characterization, and Sensory Profiling of Novel Pepper Distilled Spirit.

This study described the production method of novel whiskey using black pepper berries as raw material including the determination of chemical composition and sensory profile of this distillate. The production process consisted of production of fermentation medium via hydrothermal treatment, followed by fermentation and distillation. The incorporation of hydrothermal extraction process makes this whiskey production process differ from the existing commercial spirit production protocol. Chemical composition analysis showed that there were 12 main volatile compounds that contribute to the aroma profile of this pepper whiskey which consisted of 1 aldehyde group, 3 ester groups, 2 phenolic compounds, and 6 alcohol groups. All of these compounds are presented at different concentrations that are able to give pleasant and signature aroma to this spirit. A 10-member descriptive analysis panel conducted showed that 7 descriptors can be used to define the organoleptic quality of this whiskey, namely, clarity and brilliance (visual), fruity and flora (aroma), spiciness and sweetness (taste), and fruity mouthfeels. In conclusion, pepper berries can be used as raw material for pepper whiskey production and having organoleptic quality acceptable for human consumption.

Identification of endogenous and episomal piper yellow mottle virus from the leaves and berries of black pepper (Piper nigrum)

Piper yellow mottle virus (PYMoV) is the most frequently occurring virus causing mottle disease in black pepper plants in Sukabumi, West Java. As a pararetrovirus, PYMoV occurs in the plant as endogenous (inactive) and episomal (active, infectious) forms. Research was carried out to detect and identify PYMoV from leaf and berry samples by polymerase chain reaction (PCR) and reverse transcription-PCR (RT-PCR) followed by sequencing and nucleotide sequence analysis. Both endogenous and episomal forms of PYMoV were successfully detected from leaf and berry samples, although the endogenous form was more numerous than the episomal form. Results from black pepper berries proved the existence of both forms within single plants. It was further confirmed that endogenous and episomal PYMoV from the leaves and berries of the same plant had identical sequences, indicating the same isolates. This study is the first report of an endogenous and episomal form of PYMoV in a single plant.

Efficacy of Different Solvent for Oleoresin Extraction and Physicochemical Properties of White Pepper Produced Via Water Retting

Initially, four different solvents were compared to determine the best solvent for white pepper oleoresin extraction. Methanol was chosen as it resulted in the highest yield and total phenolic content (TPC) of oleoresin extract from white pepper. This study was also carried out to determine the functional and physicochemical properties of white pepper produced via water retting. Fresh pepper berries were soaked in distilled water (1:2, w/w) at four different temperatures of 28, 35, 42, and 49 °C for 16 days. The yield, oleoresin content, colour, fracturability, free radical scavenging activity, and TPC of white pepper produced were determined on the 4th, 8th, 12th, and 16th day of the retting process. Results showed that 8 days of retting at 28 °C was sufficient to produce a significantly (p < 0.05) high yield and most fractured white pepper. For other properties, it was suggested that retting time of 8 days was sufficient to produce satisfactory whiteness value, piperine content, free radical scavenging activity, and TPC. Therefore, it can be concluded that the quality of white pepper very much depended on retting temperature compared to the duration of the retting process.

The improvement of white pepper quality using ozone application

The processing of white pepper is still done in the traditional way so that it has low quality. To improve the quality of white pepper has been tried using the ozone application. This research aimed to study characteristics of white pepper using ozone application. The experiment designed Randomized Complete Design (CRD) with two factors and three replications. The first factor was water soaking duration (4 and 6 days). The second factor was an ozone application for 0, 20, 40 and 60 minutes using an ozone generator. The analysis performed on physical, chemical, microbiological and flavor parameters. The results showed that the best treatment was soaked for 6 days and combined with soaking in 0.25 ppm ozonated water for 20 minutes. This condition produced white pepper according to the SNI standards with characteristics: yield of 28.55 ± 0.6%, bulk density of 622.77±17.8 g/l, moisture of 11.45 ± 0.5%, dark pepper berries of 0.94 ± 0.2%, foreign matter of 1.03 ± 0.20%, piperine content of 4.89 ± 0.12%, essential oil of 2.60 ± 0.02%, lightness of 35.10 ± 4.21, TPC of 1.25 x 102 CFU/g, and butanoic acid as an off-flavor were not detected.

The influence of acute water stresses on the biochemical composition of bell pepper (Capsicum annuum L.) berries.

Crops are exposed to recurrent and acute drought stress episodes during their vegetative and reproductive cycles, and these episodes are increasingly frequent due to ongoing climate change. Sweet pepper (Capsicum annuum), alias bell pepper, is one of the most widely cultivated vegetables and is grown in open fields worldwide. Here we assessed the effect of acute water stress, applied to a breeding line of sweet pepper at three stages of plant development: five true-leaves (Stage 1), production of the third flower (Stage 2) and setting of the first fruit (Stage 3), on the production and biochemical composition of its ripe fruits. The water stress at Stages 1 and 2 induced a delay in fruit ripening, while at Stage 3 caused a drop in production. The biochemical composition of ripe fruits was assessed by quantifying their content in vitamin C, sugars, organic acids, flavonoids as well as 190 volatile organic compounds, mainly belonging to the chemical classes of hydrocarbons, alcohols, ketones, esters, terpenes, aldehydes and ethers. Our results highlight that, at different stages of plant development, acute water stresses modulate differently the accumulation of bioactive compounds in fruits, which play a key role in setting the redox-status and osmotic adjustment of the plant. This was also the case for volatile compounds since, within each chemical class, different compounds varied their content in ripe fruits. On the whole, our results demonstrate that water stresses potentially affect the organoleptic and sensory qualities of bell pepper fruits depending on when they occur. © 2021 Society of Chemical Industry.

In silico assisted identification of peppery aroma compound ‘rotundone’ backbone genes from black pepper

Rotundone, an oxygenated sesquiterpene compound, responsible for the peppery aroma. The importance of the rotundone in the flavor industry warrants search for the precursor genes in plants. We report in this study, the first on the identification of rotundone backbone genes viz., α-guaiene synthase & α-guaiene oxidase in black pepper. We identified the precursor genes of rotundone using berry transcriptome profiling. The metabolite profiling using head space mass spectrometry showed the presence of the direct precursor compounds for rotundone biosynthesis in black pepper berries. The identification of the genes & compounds of the guaiene skeleton is expected to help in bioprospecting of black pepper varieties & also in recombinant production of the aroma compound. Communicated by Ramaswamy H. Sarma Identification of rotundone backbone genes & precursor compounds from Piper nigrum

Mass modelling of pepper berries (Piper nigrum L.) with some physical properties

The determination of correlations between mass with its physical properties such as dimensions, volume and projected area is crucial in the design and development of some post-harvest processing. In this study, the physical properties were measured, and the mass of Kuching pepper berries variety was predicted in four models including Linear, Quadratic, S-curve and Power. Thus, the study was aimed to determine the most applicable model for predicting pepper berry mass with their physical properties and determine some physical properties of pepper berries to form essential and useful information. The results showed that mass modelling based on the actual volume of pepper berries was more applicable compared to other properties with the highest determination coefficient, 0.995 at 1% probability level. From the economic standpoint, predicting mass based on actual volume as Quadratic form: M = 0.828 - 0.015X + 7.376 x 10-5X 2 is recommended. This study can be applied for improvement in handling and packaging system in future.

Effect of Blanching Time and Drying Method on Quality of Black Pepper (Piper nigrum)

Quality of black pepper highly depends on pre-drying treatment and drying method. A pre-drying treatment, blanching (dipping in boiled water), is practiced in different countries. However, Bangladesh is yet to follow this technique to produce black pepper. So, this study investigated the effect of blanching, blanching time, and drying method on¬¬¬ black pepper quality. Pepper berries were treated in boiled water (blanched) for 1, 2, 3, 4, 5 minutes and kept fresh (untreated). Both treated and untreated pepper berries were dried under the open sun and in a mechanical dryer. Results showed that blanching time negatively correlated with drying duration for both mechanical and sun-drying method. Blanching limited the moisture content of dried pepper 5.33-11.52%, where the moisture content of untreated sun-dried black pepper was more than 12%. Mechanical dryer needed the lowest time over open sun-drying and decreased the moisture % to a safer level (<10%). The moderately blanched (1-3 min) black pepper was attracted by the consumers due to its uniform shiny black color. In contrast, untreated pepper could not meet the consumers' desire. Again, blanching for longer time deteriorated black peppers’ color and consequently decreased consumers' preference level to buy.

Some Physical Properties and Mass Modelling of Pepper Berries (Piper nigrum L.), Variety Kuching, at Different Maturity Levels

Pepper berry (Piper nigrum L.) is known as the king of spices and has sharp, pungent flavour and aroma. In this study, the physical properties (weight, dimensions, sphericity, volume, surface area, and projected area) were measured, and the mass of pepper berries of the Kuching variety at different maturity levels (immature, mature, and ripe) was predicted using four models: linear, quadratic, s-curve, and power. When the models were based on volume and projected area, the mass could be predicted with maximum precision. The Quadratic model was best fitted for mass prediction at all mass maturity levels (immature, mature, and ripe). The results showed that mass modelling based on the actual volume of pepper berries was more applicable compared to other properties with the highest determination coefficient, 0.995, at the 1% probability level. From an economical point of view, mass prediction based on actual volume in the Quadratic form, M= 0.828 − 0.015 V + 7.376 ×10−5V2, is recommended. The findings of physical properties and mass modelling of the berries would be useful to the scientific knowledge base, which may help in developing grading, handling, and packaging systems.

Kinetics of Quality Changes in Soaking Water during the Retting Process of Pepper Berries (Piper nigrum L.)

There are organic matters and bioactive compounds naturally present in pepper that may have leached out into the soaking water due to a prolonged retting process that caused changes in water quality. This study was carried out to determine the influences of different quantities of mature pepper berries and soaking time on the quality of soaking water during the retting process. The soaking test was conducted by having three tanks with different quantities of pepper berries soaked in the 18 L of water. The results show that the tank with the highest quantities of pepper berries has the highest increment of turbidity from 21.80 ± 1.90 NTU to 1103.30 ± 23.10 NTU (98%), the highest reduction in pH from 6.99 ± 0.02 to 3.67 ± 0.02 (47.50%), the highest reduction in dissolved oxygen from 5.19 ± 0.17 mg/L to 1.05 ± 0.02 mg/L (79.77%) and the highest increment of chemical oxygen demand from 21.67 ± 1.15 mg/L to 3243.33 ± 5.77 mg/L (99.33%) compared to other tanks. Furthermore, the zero, first and second-order kinetic models fitted well with the experimental data of the quality of soaking water for three conditions using the Arrhenius law approach. Thus, these findings are useful for estimating water quality during the retting process.

Identification of Stress-related Proteins during the Growth and Development of Piper nigrumL.

Piper nigrum L., also known as the pepper plant, produces pepper berries, which is a spice used worldwide. Changes in the natural environment have forced the plant to undergo acclimatization for plant growth. Consequently, un-adapted plants developed unhealthy, stunted growth, affecting the production of pepper berries, and thus, causing loss to agriculture. Proteomic analysis using two-dimensional polyacrylamide gel electrophoresis (PAGE) coupled with mass spectrometry was used to compare the differentially expressed proteins between healthy and unhealthy pepper plants. The proteins were successfully extracted from the stems and roots of P. nigrum and the two-dimensional protein profiles were compared. Two-dimensional analysis has indicated significant differences between the healthy and unhealthy parts with 41 and 25 differentially expressed proteins in the stems and roots respectively. A total of 10 differentially expressed proteins, characterized as unique (2) and over-expressed (8) proteins, from both plant parts were selected and sent for identification through matrix-assisted laser desorption/ionization, time-of-flight mass spectrometry. The unique and over-expressed proteins in the unhealthy stems were identified as stress-related small heat shock proteins (sHSPs). These proteins act as a chaperone to protect other proteins against a stressful environment for plant defence and adaptation. Meanwhile, over-expressed proteins from the roots were found to be peroxidase 5, malate dehydrogenase, mitochondrial and gamma-glutamyl phosphate reductase which are involved in oxidative stress, photosynthetic activity, and plant development, respectively. The findings of the differentially expressed proteins in this study, therefore, may create opportunities for further investigations of stress management control and help to improve plantation practices in the future.