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Paul W. Wilson, Gloria B. McClure, and Julian C. Miller Hall

The demand for hot sauce products continues to expand in the U.S. In the case of jalapeno pepper sauce, there are many cultivars available for sauce production but those best suited for processing have not been adequately determined. Six cultivars (four replications) of jalapeno peppers (`Coyame', `Grande', `Jalapeno-M', `Mitla', `Tula' and `Veracruz') were evaluated for mash fermentation. The attributes studied during mash aging were color spectra, capsaicin content and fermentable sugars. Fructose and glucose were the predominant sugars in jalapeno peppers and these sugars were utilized gradually with time indicating slow fermentation by microorganisms in the 15% salt mash. Capsaicin and dihydrocapsaicin were the predominant capsaicinoids in the jalapeno peppers with `Tula' containing the greatest concentration and `Veracruz' the least. All mashes displayed an apparent and unexpected rise in measurable capsaicinoids up to 6 months with a decline at 12 months. Color changes in the pepper mash were rapid initially but slowed after the first month of fermentation. Percent reflectance in fresh ground peppers was strongest in the range of 550–560 nm but, after salting, reflectance shifted to 580–590 nm and remained throughout the fermentation. Based on the characteristics tested, any of these cultivars would make a suitable mash for sauce. The heat content of the final product could be controlled by cultivar selection or through blending.

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Jian Xin Shi, Joseph Riov, Raphael Goren, Eliezer E. Goldschmidt, and Ron Porat

Pyruvate decarboxylase (PDC) and alcohol dehydrogenase (ADH) are two enzymes specifically required for ethanol fermentation. Pyruvate decarboxylase catalyzes the irreversible conversion of pyruvate to acetaldehyde (AA), and ADH subsequently

Open access

Adam D. Karl, Michael G. Brown, Sihui Ma, Ann Sandbrook, Amanda C. Stewart, Lailiang Cheng, Anna Katharine Mansfield, and Gregory M. Peck

tannin concentrations, fermentation kinetics, and cider sensory attributes ( Boudreau et al., 2017a ; Lea and Beech, 1978 ; Santos et al., 2016 ; Wargo et al., 2003 ). There are currently no standard nitrogen fertilization recommendations for cider

Open access

Adam D. Karl, Michael G. Brown, Sihui Ma, Ann Sandbrook, Amanda C. Stewart, Lailiang Cheng, Anna Katharine Mansfield, and Gregory M. Peck

affect economic returns, fruit quality, fermentation dynamics, and the sensory attributes of the finished product. Nitrogen is a macronutrient that is essential for plant metabolism, and its role in fresh-market apple production is well studied ( Cheng

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Marvin L. Baker

Fermentation and other seed pregermination treatments of Mayhaw [Crataegus opaca (1.) Hook and Arn-Series Aestivales] (Vines,; Phipps, 1988) were evaluated as potential requirements to increase germination percentages. Low seed germinability and arratic seedling emergence are major problems in Crataegus breeding. Freshly harvested fermented open-pollinated seed from 5 different Mayhaw selections averaged 93.4% at 8 days fermentation and 92.8% at 4 days fermentation. Frozen fruit stored from these 5 selections and later fermented 12 days showed the following higher percentages of germination: frozen storage for 10 days - 87.2% (<4 days fermentation (df); frozen storage for 20 days - 83.8% (<4 days df; frozen storage for 30 days - 74.4% (<8 df; frozen storage for 40 days - 72.6% (<4 df; frozen storage for 60 days - 70.2% (<4 df and frozen storage for 90 days - 60.8% (< 8 df. Positive responses to short fermentation durations (<8 days) were observed, but longer fermentation durations were deleterious. Embryo dormancy requiring acid treatment or stratification and problems with germination inhibiting substances were minimized by fermenting fresh ripened fruit containing large embryos. The fruits and seed were not allowed to dry and they were either prepared immediately or frozen for later use.

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Hisashi Kato-Noguchi

Glycolysis has been shown to accelerate in many plant species, and the glycolytic pathway was considered to replace the Krebs cycle as the main source of energy when O2 becomes limiting. The increase in glycolytic flux is accompanied by the accumulation of glycolytic end products, including ethanol and lactate. Lactate dehydrogenase (LDH) has been isolated from several plant sources; however, there is very little work reported on LDH induction during anaerobiosis and no information is available on the long-term effect of low O2 atmosphere on lactic fermentation in carrot (Daucus carota L.) roots. To understand the regulation of metabolism of lactic fermentation, carrot root shreds were stored under a continuous flow of 0.5% and 2% O2 (balance N2), or air at 5°C and 15°C. The concentration of lactate and the activity of LDH increased rapidly, reached peaks after 2 days, and then gradually decreased. The maximum increase level of LDH was 2.8-, 2.1-, 2.0-, and 1.6-fold; that of lactate was 5.6-, 3.8-, 2.9-, and 2.6-fold for 0.5% O2 at 15°C and 5°C, and 2% O2 AT 15°C and 5°C, respectively, compared with corresponding air control. These results indicate that the lactic fermentation was more accelerated in 0.5% O2 than 2% O2 atmosphere, and more accelerated at the higher storage temperature than the lower one. However, ethanol accumulation, which was found in the carrots under the same low-O2 atmosphere, was much more than lactate accumulation. Thus, carrot roots possess LDH, which appears under low-O2 atmosphere, but lactic fermentation may be a minor carbon flux compared to ethanolic fermentation.

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Dangyang Ke, Elhadi Yahia, Mila Mateos, and Adel A. Kader

Changes in fermentation volatiles and enzymes were studied in preclimacteric and postclimacteric `Bartlett' pears (Pyrus communis L.) kept in air, 0.25% O2, 20% O2 + 80% CO2, or 0.25% O2 + 80% CO2 at 20C for 1, 2, or 3 days. All three atmospheres resulted in accumulation of acetaldehyde, ethanol, and ethyl acetate. The postclimacteric pears had higher activity of pyruvate decarboxylase (PDC) and higher concentrations of fermentation volatiles than those of the preclimacteric fruit. For the preclimacteric pears, the 0.25% O2 treatment dramatically increased alcohol dehydrogenase (ADH) activity, which was largely due to the enhancement of one ADH isozyme. Exposure to 20% O2 + 80% CO2 slightly increased ADH activity, but the combination of 0.25% O2 + 80% CO2 resulted in lower ADH activity than 0.25% O2 alone. For the postclimacteric pears, the three atmospheres resulted in higher PDC and ADH activities than those of air control fruit. Ethanolic fermentation in `Bartlett' pears could be induced by low O2 and/or high CO2 via 1) increased amounts of PDC and ADH; 2) PDC and ADH activation caused by decreased cytoplasmic pH; or 3) PDC and ADH activation or more rapid fermentation due to increased concentrations of their substrates (pyruvate, acetaldehyde, or NADH).

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Hisashi Kato-Noguchi and Alley E. Watada

Carrot (Daucus carota L.) root shreds were stored under a continuous flow of 0.5% and 2% O2 (balance N2) or in air for 7 days at 5 and 15 °C to study the regulation of ethanolic fermentation metabolism. Low-O2 atmospheres of 0.5% and 2% caused increases in ethanol and acetaldehyde concentrations and the activities of alcohol dehydrogenase (ADH) and pyruvate decarboxylase (PDC) compared to air. By day 3, ethanol increased 38-, 25-, 13-, and 9.5-fold; acetaldehyde increased 20-, 13-, 7.7-, and 5.6-fold; ADH increased 7.6-, 6.3-, 3.8-, and 2.7-fold; and PDC increased 4.2-, 3.9-, 2.3-, and 2.2-fold in samples at 0.5% O2 at 15 or 5 °C and at 2% O2 at 15 or 5 °C, respectively, compared with corresponding samples in air. These results indicate that ethanolic fermentation was accelerated more in the 0.5% than in the 2% O2 atmosphere and more at 15 °C than at 5 °C. The acceleration of ethanolic fermentation may allow production of some ATP, which may permit the carrot tissues to survive.

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Diana Dostal Lange and Randolph M. Beaudry

Low O2 and high CO2 concentrations can be used effectively to slow respiration and retard decay, but anaerobic and C02-injurious conditions must be avoided. The objective of this research was to: 1) determine the effects of low O2 and very high-C02 on flavor quality and accumulation of fermentation products. Strawberries and blueberries were stored in 2% O2/0% CO2, 20% 02/50% CO2, 2% O2/50% CO2, and 20% 02/0% CO2 for 0, 2, 4, 6, and 8 days at 20C. A taste panel evaluated the berries at the end of each storage period and again after 2 days under ambient conditions. Ethanol was the primary fermentation product that accumulated in response to low O2 and high CO2 concentrations. However, acetaldehyde was produced preferentially in response to elevated C02 levels. The flavor quality of the strawberries and blueberries was only acceptable for 2 days for treatments containing 50% CO2. The most intense off-flavors were detected in the 2% 02/50% CO2 and 20% O2/50% CO2 samples. 50% CO2 was highly effective in preventing decay, but this concentration was too high for acceptable flavor quality for storage periods greater than 2 days.

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Brianna L. Ewing and Barbara A. Rasco

and are therefore destined for cider processing via alcoholic fermentation. These cultivars are in relative short supply and, therefore, are more expensive in the United States, so blending with and use of dessert and culinary apples is necessary for