Dry Almond Research Articles

Nutritional and Anti-Nutritional Compositions of Kernel Almond Flour from Kent Variety Mango (Mangifera Indica L.) Grown in Northern Côte d’Ivoire

Mango is an important tropical fruit around the world which is subject of large-scale production and extensive marketing. Unfortunately, much of its production is discarded as waste, usually consisting of its peel and kernel. This leads to high losses in mango sector and also ecological problems. This study aims to characterize nutritional and anti-nutritional properties of almond flour from Kent mango kernel. Also, after sampling Kent kernels from dried mango factories of Korhogo (Northern Côte d’Ivoire), they were washed and sun dried at 32- 35°C for 10 hours a day during 8 days. The drying mango kernels were peeled and almonds inside were removed, cut into small pieces and sun-dried to constant mass. The dry almond were crushed to obtain flour. Some nutritional and anti-nutritional properties of flour were determined. For nutritional compositions, analysis show that almond flour contains 7.6±0.35% moisture, 4.25±0.04% protein, 16.14±0.21% lipids, 1.95±0.15% ash and 70.06±0.56% carbohydrates. In addition, this almond flour contains amino acids which are mostly including lysine and leucine with respectively content of 64.19% and 13.89%. Also, flour contains minerals between 1.70 and 0.2 % which most important are potassium, magnesium, calcium and phosphorus. The almonds flour is composed of vitamin C and vitamins B1, B2 and B9. Concerning anti-nutritional factors, analysis of almond flour show that it contains tannins and phytates with respectively content of 119.27±1.47 mg/100g and 65.82±0.28 mg/100g. These above results show that almond flour of Kent mango kernel can be used for food purposes after elimination of anti-nutritional factors.

Drying and disinfection of off-ground harvested almonds using step-down temperature hot air heating

This study aimed to develop a simultaneous drying and disinfection method for off-ground harvested almonds to improve drying efficiency and product safety. Almonds were dried in a column dryer (0.57 m-height) with hot air under constant temperature (ambient, 40, 50 and 60 °C) or step-down temperature (preheating with 80 °C and 90 °C, holding for 1–3 h, then stepping down to complete drying at 60 °C) and 1.0 m/s velocity. The drying time ranged from 240 to 2160 min to dry almonds from initial moisture content of 0.41 kg water/kg wet mass to a targeted 0.12 kg water/kg wet mass. Specific energy consumption ranged from 14.3 to 22.0 MJ/kg. No cavity, significant color change, concealed damage or oil quality deterioration were observed under all tested conditions. Step-down temperature drying with holding achieved up to 0.8 log CFU/g total bacterial counts reduction of in-shell almonds. Drying in-shell almonds saved up to 75% drying time and 78.6% specific energy consumption compared to drying in-hull almonds under the same temperature, with more uniform final moisture distribution. The findings suggested off-ground harvested almonds should be sorted and de-hulled prior to drying, which could significantly improve the drying efficiency, moisture uniformity and throughput of the drying process.

Determination of thermophysical properties of cupuassu (Theobroma grandiflorum) dry almonds

In comparison to cocoa, little has been reported on the drying of cupuassu almonds that can be used to produce cupulate, a chocolate type product. Thus, in this study thermophysical properties of cupuassu dry almonds (moisture = 9.68 % d.b.) were determined as: thermal conductivity (k) of 0.14 kW/(m.K), specific heat (cp) of 2.86 kJ/(kg.K), thermal diffusivity (?) of 4.8·10-5 m²/s, effective diffusivity (Deff) of 9.94·10-10 - 6.29·10-10 m²/s and activation energy (Ea) of 14.90 kJ/mol. These results showed a similarity of values between cupuassu and cocoa and allows to perform more specific studies for the development of dryers for the cupuassu almonds.

Wetting raw almonds to enhance pulse light inactivation of Salmonella and preserve quality

The overall goal was to explore the potential of using pulsed light (PL) to pasteurize raw almonds. PL treatment of dry almonds was found to be not effective and detrimental to the almond quality due to the excessive heat generated by PL. Dipping almonds in water before PL treatment enhanced the inactivation of Salmonella dipped-inoculated on almonds and better preserved almond quality by slowing down the temperature increase through water evaporation from almonds. The effects of PL intensity, treatment time, almond sample size, and times of almond dipping in water on Salmonella inactivation were determined. All these parameters played an important role in the inactivation of Salmonella. Increasing the PL intensity and extending the PL treatment time resulted in greater Salmonella inactivation. On the other hand, increasing the almond sample size from 50 g to 500 g and number times of water dipping from one to two slowed down Salmonella inactivation. The one-time dipping of almonds in water for 1 min followed by a PL treatment of 500 g of almonds at an intensity of 0.75 W/cm2 for 18 min could achieve at least 5 log reduction of Salmonella. Hence, this treatment was chosen to process 500 g of un-inoculated almonds for color and quality analysis. This treatment slightly affected the almond color, but did not significantly increase the lipid oxidation of almonds both immediate after processing and after storage at 39 °C for 11 days. No significant difference in the appearance and color of almond between the untreated control and the PL-treated almonds was observed visually. Therefore, this PL treatment in combination with prior water dipping could be a potential pasteurization method for raw almonds.

Retort-heating carbonisation of almond (Terminalia catappa) leaves and LDPE waste for biochar production: evaluation of product quality

ABSTRACT The aim of this study was to utilise a top-lit updraft biomass conversion reactor with retort heating for the production of biochar from dry almond (Terminalia catappa) leaves and Low-Density Polyethylene (LDPE) waste (biomass-plastic mass ratio of 35:1). The feedstock was chosen to serve as a typology of each of the two major constituents of municipal solid waste (MSW). The study was done to examine the process performance and product yield and quality. A yield of 28.57 wt% for the biomass biochar and 71.43 wt% for the hybrid biochar was achieved at a peak temperature of 494°C and 362°C respectively in 90 minutes. The products were characterised using Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and Branueur–Emmett–Teller (BET) analyses. The biomass biochar and the hybrid biochar have a specific surface area of 450.2 m2/g and 296.8 m2/g respectively and both products was mesoporous. It is observed that retort heating carbonisation can be used to convert almond leaves and LDPE waste to biochar usable as an adsorbent. The work is of benefit in converting MSW to a useful product. These are helpful in waste minimisation, environmental protection.

Development of a Stockpile Heated and Ambient Air Dryer (SHAD) for Freshly Harvested Almonds

HighlightsAlmonds are conventionally sun-dried on the orchard floor. Collection and removal of dried nuts from the orchard generates significant dust.Almonds were dried on-farm directly from the almond tree eliminating field drying.SHAD dryer uses a combination of heated and ambient air to dry almonds in a stockpile.The dryer has a SMER of 0.64 kg/kWh, MER of 1.02 kg/h, and COP of 1.33.Abstract. Dust generated by farming activities is a safety hazard to farmworkers and an environmental contaminant. During the almond (Prunus dulcis) harvest in California, dust is primarily generated by the mechanized movement of almonds disturbing the bare soil of the orchard floor, during the sun-drying, windrowing process, and as they are transferred into trucks for transport to processing facilities. Off-ground dust-less harvesting will only be achieved when the almond industry adopts feasible mechanical drying methods. Therefore, a stockpile heated and ambient air dryer (SHAD) was developed to determine the feasibility of dehydrating almonds (Var. ‘Monterey’). A stockpile containing 4,155 kg of almonds was created and almonds were dehydrated from their initial 12.6% almond kernel dry-basis moisture content (MCdb) to final MCdb of 6.04%. Drying was achieved as a combination of heated air at a temperature of 55°C in the drying plenum with airflow of 0.078 m3/s per m3 of fresh almonds. After drying, almond quality parameters were measured, including damage by molds or decay, insect injury, and presence of internal cavities. Drying energy consumption, cost, and performance indicators were also determined. The differences in MCdb between the bottom, middle, and top layers of the almond stockpile were significant (p = 0.05). Post-hoc Tuckey test was conducted which indicated that the MCdb in the top layer was significantly lower than almond MCdb in the middle and bottom layers. Results showed that damage by molds or decay, insect injury, and internal cavities were 1.81%, 0%, and 1.77%, respectively, after drying. Therefore, the overall almond quality was not compromised. The drying process cost $11.65 per tonne of the initial weight of almonds with a Specific Moisture Extraction Rate (SMER) of 0.64 kg/kWh, Moisture Extraction Rate (MER) of 1.02 kg/h, and a Coefficient of Performance (COP) of 1.33. Comparison with other dryers in the literature shows that SMER and MER were within limits. However, a low COP was observed. Keywords: Dust, Energy, Postharvest, Stockpile drying, Tree nut.s

Lessons learnt from on-farm mechanical drying of almonds in 2017

In order to collect almonds earlier from the field to minimise weather damage, and manage rain affected almonds, several almond growers in Australia used three different types of dehydration facilities for drying bulk almonds. These systems were fitted with temperature and relative humidity sensors placed in with the almonds at fixed locations. From knowing the moisture status of the air in the bulk almonds and that of ambient conditions, aeration fans were selectively run to condition the almonds to a desired kernel moisture content. Firstly, early season over dried almonds were re-humidified in a shed with a vented floor. The shed was also used to finish dry later season higher moisture almonds. Secondly, stockpiles of almonds with a central aeration vent running along the length of the stockpile and aeration fans at each end were used to finish dry almonds. Tests showed using fans at both ends dried the almonds quicker than using only one fan at one end. Aeration of an uncovered 50 m long stockpile (no tarp) was measured to be uniform and effective along its length. Thirdly, the performance of four modified 12 m open top shipping containers with a false perforated floor was monitored for the drying of end of season rain affected second shake almonds using heated air. It was found that by aerating the very wet almonds for 24 h with heated air and then letting them sit for several days a 6% kernel moisture content could be achieved. The monitoring provided the operators with an insight into the progressive drying of the almonds and provided data for dehydration management decisions. The placing of sensors in the container dehydrators highlighted the need to improve the uniformity of air flow into the almonds. The work showed that the dehydration facilities can be used to reduce the time almonds need to remain in the orchard and thus reduce losses from weather and other sources of damage.

The chemical composition and in vitro digestibility evaluation of almond tree (Prunus dulcis D. A. Webb syn. Prunus amygdalus; var. Shokoufeh) leaves versus hulls and green versus dry leaves as feed for ruminants

The current study aimed to evaluate the chemical composition and in vitro digestibility of almond tree (Prunus dulcis D. A. Webb syn. Prunus amygdalus; var. Shokoufeh) leaves versus hulls, and green versus dry leaves as feed for ruminants. The fresh green almond hulls (GAH) and leaves (GAL) were harvested and spread under a shade to dry. Dry almond leaves (DAL) were collected from under the trees where as dry almond hulls (DAH) were collected 4 weeks after harvesting the fresh samples. The chemical composition of substrates was determined using standard approaches and the metabolisable energy (ME), in vitro dry matter (DMD) and in vitro organic matter (OMD) digestibility were measured using the in vitro gas production (GP) technique. The GAL contained 81 g crude protein (CP) kg−1 DM while DAH contained 103 g CP kg−1 DM. The CP was higher (P = 0.0003) in dry (leaves and hulls) than in green (leaves and hulls) samples. The ash content ranged from 99.2 to 181.5 g kg−1 DM in DAH and DAL, respectively, (P = 0.0041). The ether extract content ranged from 27 for DAH to 65 g kg−1 for DAL (P = 0.0018). The acid detergent fibre and neutral detergent fibre content ranged from 185 to 304 and 444 to 620 g kg−1 DM (P = 0.04), for GAL and DAH, respectively. The DAH had the highest (P = 0.0001) GP24 and GP96. The DAH had the highest (P = 0.0001) potential GP (i.e., b), while the GP rate was highest for GAL and GAH (P = 0.034), ME was highest for DAH (P = 0.0001), and in vitro OMD was highest for DAH (P = 0.0001). The highest DMD (P = 0.0001) values were obtained with DAH followed by GAL, DAL and GAH, respectively. It can be concluded that almond hulls and leaves have a good nutritional potential to cover the maintenance nutrient requirements of small ruminants. Almond hulls and leaves can also be used as supplement to low quality mature pasture and/or crop residues. However, more studies are warranted to better characterize these feeds in in vivo animal feeding trials.

Comparison of the volatile emission profiles of ground almond and pistachio mummies: Part 2 – Critical changes in emission profiles as a result of increasing the water activity

Pistachio and almond mummies have been reported to attract adult navel orangeworm moths in field trapping studies. The volatile profiles of these matrices were recently described. Concurrently, recent investigations have demonstrated that the water activity of almond hulls plays an important role in the production of semiochemicals known to attract the navel orangeworm in almond orchards. In the present study, the water activity of pistachio and almond mummies was increased and the resultant headspace volatiles monitored over the course of a week. The volatile profile of wet pistachio mummies contained 86 volatiles, of which 22 were unique to the wet matrix. The volatile profile of the wet pistachio matrix increased in chemical diversity to include small chain alcohols, benzenoids, and fatty acid breakdown products relative to the dry matrix, which primarily emitted terpenoids. The wet almond mummies emitted a total of 57 volatiles, 37 more than dry almond mummies. Among the volatiles detected in the wet almond mummies were three of the five compounds that are found in the synthetic blend of host plant volatiles known to attract navel orangeworm moths. The volatile bouquets from the wet and dry pistachio mummies, and wet almond mummies were evaluated by electroantennographic (EAG) analysis.

Cold Plasma Reduction of Salmonella and Escherichia coli O157:H7 on Almonds Using Ambient Pressure Gases

Contamination of raw nuts, including almonds, is a food safety concern. Cold plasma is a novel antimicrobial intervention that can eliminate foodborne pathogens. The objective of this work was to evaluate the efficacy of rapid cold plasma treatments in eliminating Salmonella and Escherichia coli O157:H7 from dry almonds. Three isolates of Salmonella (S. Anatum F4317, S. Stanley H0558, and S. Enteritidis PT30) and 3 isolates of E. coli O157:H7 (C9490, ATCC 35150, and ATCC 43894) were separately grown and spot-inoculated (10 μL) onto whole almonds and allowed to dry for 10 min. Inoculated almonds were treated with a cold plasma jet, with treatment variables evaluated in a factorial design for each isolate: time, distance, and feed gas. Treatment time was 0 s (control), 10 s, or 20 s. Distance from the emitter was 2, 4, or 6 cm. Feed gas was dry air or nitrogen. After treatment, the almonds were sampled using swabs. Survivors were enumerated on tryptic soy agar (TSA) plates. Cold plasma significantly reduced both pathogens on almonds. The greatest reduction observed was 1.34 log cfu/mL reduction of E. coli O157:H7 C9490 after 20 s treatment at 6 cm spacing. The interaction of treatment time with distance from plasma emitter head was complex, and isolate-dependent. Longer duration of treatment did not always result in enhanced reductions. In general, nitrogen as a feed gas resulted in a reduced antimicrobial efficacy compared to dry air. These results indicate that short pulses of atmospheric pressure cold plasma can significantly reduce Salmonella and E. coli O157:H7 on almonds.

Comparative study of tocopherol homologue content in four almond oil cultivars during two consecutive years

In this study, a quick and easy analytical method was optimised to obtain the tocopherol (T) profile of almond oil samples in less than 18 min including the sample preparation process. As the tocopherol determination is being carried out on the almond oil, a previous optimisation step to analyse moisture and fat is simultaneously carried out. Additionally, the method was applied to the analysis of four almond cultivars (Marcona, Guara, Garrigues and Butte) cultivated in different locations during the 2004 and 2005 growing seasons. α-T mean values for the almond samples included in the study varied from 8.5 to 19.4 mg/100 g of dry almond. β+γ-T values ranged from 0.141 to 0.838 mg/100 g of dry almond. Meanwhile, δ-T was found in trace quantities in all almonds. After applying an ANOVA analysis to the data, Marcona samples were found to be significatively different to the other three cultivars included in the analysis on the basis of α-T and β+γ-T content. Moreover, a study of degradation of tocopherol homologues over time was done showing that after a year of storage, shelled and unshelled almonds maintained more than 80% of the initial tocopherol meanwhile, greater losses and variabilities in β+γ-T and δ-T were observed.

Growth of Salmonella Enteritidis Phage Type 30 in Almond Hull and Shell Slurries and Survival in Drying Almond Hulls

Traceback investigation of a 2000 to 2001 outbreak of salmonellosis associated with consumption of raw almonds led to isolation of the outbreak strain Salmonella enterica serovar Enteritidis phage type (PT) 30 on three geographically linked almond farms. Interviews with these growers revealed that significant rain fell during the 2000 harvest when many almonds were drying on the ground. The objectives of this study were to document weather conditions during the 2000 harvest, determine the potential for growth of Salmonella Enteritidis PT 30 in hull or shell slurries, and evaluate survival of Salmonella Enteritidis PT 30 on wet almond hulls during drying. Dry almond hulls and in-shell kernels wetted for 24 h increased in weight by 250 to 300% and 100%, respectively. Both hull and shell slurries supported rapid growth of Salmonella Enteritidis PT 30 at 24°C; slurries containing hulls also supported growth at 15°C. Maximum Salmonella Enteritidis PT 30 concentrations of 6.2 and 7.8 log CFU/ml were observed at 15 and 24°C, respectively. Salmonella Enteritidis PT 30 grown in wet hulls that were incubated at 24°C survived drying at either 15 or 37°C. Reductions of 1 to 3 log CFU/g of dry hull were observed during drying; reductions generally declined as incubation time increased from 2 to 7 days. Evaluation of shipping records revealed that approximately 60% of outbreak-associated almonds had not been exposed to rain, eliminating this factor as the sole cause of the outbreak. However, the data provide evidence that wet almonds may be a greater risk for high concentrations of Salmonella, and specific guidelines should be established for harvesting and processing almonds that have been exposed to rain or other water sources.

Autohydrolysis of Almond Shells for the Production of Xylo-oligosaccharides: Product Characteristics and Reaction Kinetics

Almond shells are agricultural residues with a high content of xylan that are produced abundantly in some regions with a Mediterranean climate. We have studied the production of xylo-oligosaccharides from almond shells by autohydrolysis at 150−190 °C. The yield, composition, and molar mass distribution of the xylo-oligosaccharides were dependent on temperature and time: the maximum yield of xylo-oligosaccharides increased from 42% at 150 °C and 300 min to 63% at 190 °C and 19 min, while their anhydroarabinose-to-anhydroxylose and acetyl-to-anhydroxylose mass ratios were 0.039 and 0.076 at 150 °C and 0.129 and 0.125 at 190 °C, respectively. Experimental data was used to fit the parameters of a kinetic model for xylan autohydrolysis, which describes the yields of the different reaction products and accounts for the changes in the chemical composition of xylan and xylo-oligosaccharides. The recovery of the xylo-oligosaccharides by spray drying was also evaluated. Spray drying of the autohydrolysis liquor obtained at 179 °C and 23 min gave a yield of nonvolatile products of 29.4 g/(100 g of dry almond shells). The composition of this product was 58.3% xylo-oligosaccharides, 2.4% xylose, 1.5% arabinose, 0.78% glucose, 0.27% HMF, 16% Klason-type lignin, 4.8% ash, and 14.9% nonidentified products, which probably included organic extractives and protein present in almond shells, and products formed by the degradation of carbohydrates.

Improved Attractant for Navel Orangeworm (Lepidoptera: Pyralidae) Egg Traps in Almonds

Dry almond press cake was compared with standard wheat bran bait in Amyelois transitella (Walker) egg traps in California almond orchards. Trapping data from three locations in the Central Valley showed that traps containing almond press cake collected more eggs than traps with wheat bran throughout the 1980 season. The almond press cake traps were also easier to maintain and service than the wheat bran traps.